PROSPECTUS SUPPLEMENT
(To Prospectus dated March 17, 2004)

                                     ACACIA
                                    RESEARCH
                                  CORPORATION

                                3,000,000 SHARES
                    ACACIA RESEARCH-COMBIMATRIX COMMON STOCK
________________________________________________________________________________

Acacia Research Corporation is offering 3,000,000 shares of its Acacia
Research-CombiMatrix common stock. The Acacia Research-CombiMatrix common stock
is intended to reflect the performance of Acacia Research Corporation's
CombiMatrix group. Holders of Acacia Research-CombiMatrix common stock, however,
are common stockholders of Acacia Research Corporation and are subject to all of
the risks of an equity investment in Acacia Research Corporation and all of its
businesses, assets and liabilities.

Our Acacia Research-CombiMatrix common stock is traded on the Nasdaq National
Market under the ticker symbol "CBMX." The last reported sales price of our
Acacia Research-CombiMatrix common stock on April 13, 2004, was $5.53 per share.

In connection with this offering, we will pay fees to the placement agents. See
"Plan of Distribution" beginning on page S-14 of this prospectus supplement for
more information regarding these arrangements.

________________________________________________________________________________

INVESTING IN OUR COMMON STOCK INVOLVES RISKS. SEE "RISK FACTORS" BEGINNING ON
PAGE S-1.
________________________________________________________________________________

                                                  PER SHARE           TOTAL
                                                -------------     -------------
Offering Price                                      $5.00         $ 15,000,000
Placement Agent Fees                                $0.35         $  1,050,000
Proceeds, before expenses to us                     $4.65         $ 13,950,000

We estimate the total expenses of this offering, excluding the placement agents'
fees, will be approximately $345,000. The placement agents are not required to
sell any specific number or dollar amount of the shares of Acacia
Research-CombiMatrix common stock offered by this offering, but will use best
efforts to sell the shares of Acacia Research-CombiMatrix common stock offered.
We expect that delivery of the shares of Acacia Research-CombiMatrix common
stock being offered under this prospectus supplement will be made to investors
on or about April 15, 2004. Because there is no minimum offering amount required
as a condition to closing in this offering, the actual public offering amount,
placement agents' fees and net proceeds to us, if any, in this offering are not
presently determinable and may be substantially less than the total offering
amounts set forth above.

NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED IF THIS
PROSPECTUS SUPPLEMENT IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE
CONTRARY IS A CRIMINAL OFFENSE.

________________________________________________________________________________

THOMAS WEISEL PARTNERS LLC

                                                              BREAN MURRAY & CO.


The date of this prospectus supplement is April 14, 2004



                                TABLE OF CONTENTS

                              PROSPECTUS SUPPLEMENT

Risk Factors............................................................   S-1
Special Note Regarding Forward-Looking Statements.......................   S-1
Market Price and Dividends On Our Stock.................................   S-2
Capitalization..........................................................   S-3
Selected Financial Data.................................................   S-4
Management..............................................................   S-8
The Offering............................................................  S-10
Use of Proceeds.........................................................  S-11
Dilution................................................................  S-12
Plan of Distribution....................................................  S-14
Legal Matters...........................................................  S-15

                                   PROSPECTUS
About This Prospectus...................................................     1
Our Company.............................................................     1
Risk Factors............................................................     2
Forward-Looking Statements..............................................    22
Use of Proceeds.........................................................    22
Description of Our Capital Stock........................................    23
Description of Warrants.................................................    29
Plan of Distribution....................................................    30
Experts.................................................................    31
Legal Matters...........................................................    31
Where You Can Find More Information.....................................    31
Information Incorporated by Reference...................................    32


                           __________________________

     Unless otherwise mentioned or unless the context requires otherwise, all
references in this prospectus supplement and the accompanying prospectus to "the
company," "we," "us," "our," or similar references mean Acacia Research
Corporation.

     The first part, which is this prospectus supplement, describes the specific
terms of this offering and other matters relating to us and our financial
condition. The second part, which is the accompanying prospectus, gives more
general information about securities we may offer from time to time, some of
which may not apply to the Acacia Research-CombiMatrix common stock offered by
this prospectus supplement. To the extent there is a conflict between the
information contained in this prospectus supplement, on the one hand, and the
information contained in the accompanying prospectus or any document
incorporated by reference therein, on the other hand, the information in this
prospectus supplement shall control.

     We have not authorized any dealer, salesman or other person to give any
information or to make any representation other than those contained or
incorporated by reference in this prospectus supplement and the accompanying
prospectus. You must not rely upon any information or representation not
contained or incorporated by reference in this prospectus supplement or the
accompanying prospectus. This prospectus supplement and the accompanying
prospectus do not constitute an offer to sell or the solicitation of an offer to
buy common stock, nor do this prospectus supplement and the accompanying
prospectus constitute an offer to sell or the solicitation of an offer to buy
common stock in any jurisdiction to any person to whom it is unlawful to make
such offer or solicitation in such jurisdiction. You should not assume that the
information contained in this prospectus supplement and the accompanying
prospectus is accurate on any date subsequent to the date set forth on the front
of the document or that any information we have incorporated by reference is
correct on any date subsequent to the date of the document incorporated by
reference, even though this prospectus supplement and any accompanying
prospectus is delivered or common stock is sold on a later date.

     Information that we file with the SEC subsequent to the date on the cover
will automatically update and supersede the information contained in this
prospectus supplement and the accompanying prospectus. We incorporate by
reference the documents listed in the accompanying prospectus and any future
filings made with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the
Securities Exchange Act of 1934, as amended, until we issue all of the common
stock offered pursuant to this prospectus supplement and the accompanying
prospectus.

                                      -i-


                                  RISK FACTORS

     AN INVESTMENT IN OUR ACACIA RESEARCH-COMBIMATRIX COMMON STOCK INVOLVES
VARIOUS RISKS. YOU SHOULD CAREFULLY CONSIDER THE RISK FACTORS DESCRIBED ON PAGES
2 TO 20 OF THE PROSPECTUS ACCOMPANYING THIS PROSPECTUS SUPPLEMENT, TOGETHER WITH
THE OTHER INFORMATION CONTAINED AND INCORPORATED BY REFERENCE IN THIS PROSPECTUS
SUPPLEMENT AND THE ACCOMPANYING PROSPECTUS, BEFORE PURCHASING OUR COMMON STOCK.
IF ANY OF THE RISKS DISCUSSED IN THE ACCOMPANYING PROSPECTUS ACTUALLY OCCUR, OUR
BUSINESS, OPERATING RESULTS, PROSPECTS OR FINANCIAL CONDITION COULD BE HARMED.
THIS COULD CAUSE THE MARKET PRICE OF OUR ACACIA RESEARCH-COMBIMATRIX COMMON
STOCK TO DECLINE AND COULD CAUSE YOU TO LOSE ALL OR PART OF YOUR INVESTMENT.

                SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

     This prospectus supplement contains forward-looking statements within the
meaning of the federal securities laws. Forward-looking statements are
statements that predict or describe future events or trends and that do not
relate solely to historical matters. You can generally identify forward-looking
statements as statements containing the words "may," "will," "expect,"
"believe," "estimate," "anticipate," "intend," "continue," and other similar
expressions or the negative of these terms. You should be aware that the matters
described in our forward-looking statements are subject to known and unknown
risks, uncertainties and other unpredictable factors, many of which are beyond
our control. Statements regarding the following subjects are forward-looking by
their nature:

          o    our business strategies;

          o    market trends and risks;

          o    assumptions regarding economic conditions;

          o    circumstances affecting anticipated revenues and costs; and

          o    legislative, regulatory and competitive developments.

     These forward-looking statements are subject to various risks and
     uncertainties, including those related to:

          o    the recent slowdown affecting technology companies;

          o    our ability to successfully develop products;

          o    rapid technological change in our markets;

          o    anticipated sources of future revenues;

          o    changes in demand for our future products;

          o    our ability to raise capital in the future; and

          o    the adequacy of our capital resources to fund our operations.

     Other risks, uncertainties and factors, including those discussed under
"Risk Factors" in the prospectus accompanying this prospectus supplement or
described in reports that we file from time to time with the Securities and
Exchange Commission, such as our quarterly and annual reports, could cause our
actual results to differ materially from those projected in any forward-looking
statements we make. We are not obligated to publicly update or revise any
forward-looking statements, whether as a result of new information, future
events or otherwise.

                                      S-1


                     MARKET PRICE AND DIVIDENDS ON OUR STOCK

RECENT MARKET PRICES

     Acacia Research Corporation's two classes of common stock, Acacia
Research-CombiMatrix common stock and Acacia Research-Acacia Technologies common
stock, commenced trading on the Nasdaq Stock Market on December 16, 2002. The
two classes of common stock were created as a result of Acacia Research
Corporation's recapitalization that was approved by Acacia Research
Corporation's stockholders on December 11, 2002. The two classes of stock
replaced Acacia Research Corporation's common stock formerly traded on the
Nasdaq stock market under the symbol ACRI. Acacia Research-CombiMatrix common
stock and Acacia Research-Acacia Technologies common stock are now listed on the
Nasdaq National Market System. Acacia Research-CombiMatrix common stock is
intended to reflect the performance of Acacia Research Corporation's CombiMatrix
group, and Acacia Research-Acacia Technologies stock is intended to reflect the
performance of Acacia Research Corporation's Acacia Technologies group.

     The high and low bid prices for our Acacia Research-CombiMatrix common
stock as reported by NASDAQ for the periods indicated are as follows. Such
prices are inter-dealer prices without retail markups, markdowns or commissions
and may not necessarily represent actual transactions.

                                                             HIGH          LOW
                                                             ----          ---
            YEAR ENDED DECEMBER 31, 2002:
                 Fourth Quarter                             $ 4.98       $ 2.70
            YEAR ENDED DECEMBER 31, 2003:
                 First Quarter                                3.65         1.50
                 Second Quarter                               2.83         1.71
                 Third Quarter                                5.07         2.25
                 Fourth Quarter                               5.05         2.90
            YEAR ENDED DECEMBER 31, 2004:
                 First Quarter                                9.30         3.16
                 Second Quarter (through April 13, 2004)      6.17         5.42

     On March 15, 2004, there were approximately 179 owners of record of Acacia
Research-CombiMatrix stock and approximately 160 owners of record of Acacia
Research-Acacia Technologies stock. The majority of the outstanding shares of
Acacia Research-CombiMatrix stock are held by a nominee holder on behalf of an
indeterminable number of ultimate beneficial owners.

DIVIDEND POLICY

     To date, we have not declared or paid any cash dividends with respect to
our capital stock, and the current policy of the board of directors is to retain
earnings, if any, to provide for the growth of Acacia Research Corporation.
Consequently, we do not expect to pay any cash dividends in the foreseeable
future. Further, there can be no assurance that our proposed operations will
generate revenues and cash flow needed to declare a cash dividend or that we
will have legally available funds to pay dividends.

                                      S-2


                                 CAPITALIZATION

     The following table sets forth our actual capitalization as of December 31,
2003, and our capitalization as adjusted to give effect to the issuance of
3,000,000 shares of our Acacia Research-CombiMatrix common stock in this
offering at an assumed offering price of $5.00 per share.

     The information set forth in the following table should be read in
conjunction with, and is qualified in its entirety by, the financial statements
and the notes thereto included in our Annual Report on Form 10-K for the fiscal
year ended December 31, 2003, which is incorporated by reference into the
accompanying prospectus.



                                                                                        AS OF DECEMBER 31, 2003
                                                                                  ----------------------------------
                                                                                    HISTORICAL       AS ADJUSTED (1)
                                                                                  --------------     ---------------
                                                                                       (dollars in thousands)
                                                                                               
STOCKHOLDERS' EQUITY:
Preferred stock

  Acacia Research Corporation, par value $0.001 per share; 10,000,000
      shares authorized; no shares outstanding                                    $          --      $          --

Common stock
  Acacia Research - Acacia Technologies stock, par value $0.001 per share,
      50,000,000 authorized; 19,739,984 shares issued and outstanding;
      19,739,984 shares issued and outstanding, as adjusted                                  20                 20

  Acacia Research - CombiMatrix stock, par value $0.001 per share, 50,000,000
      authorized; 26,328,122 shares issued and outstanding;
      29,328,122 shares issued and outstanding, as adjusted                                  26                 29

Additional paid-in capital                                                              244,517            258,119
Deferred stock compensation                                                                (766)              (766)
Accumulated comprehensive loss                                                                8                  8
Accumulated deficit                                                                    (183,405)          (183,405)
                                                                                  --------------     --------------
      Total stockholders' equity                                                  $      60,400      $      74,005



---------------
(1) After deducting estimated placement agent payments and estimated offering
expenses payable by us.

                                                    S-3


                             SELECTED FINANCIAL DATA

     The consolidating selected balance sheet data as of December 31, 2003 and
2002 and the consolidating selected statement of operations data for the years
ended December 31, 2003, 2002 and 2001 set forth below have been derived from
our audited consolidated financial statements for those years and should be read
in conjunction with those financial statements (including notes thereto), which
are included in our Annual Report on Form 10-K for the fiscal year ended
December 31, 2003, and incorporated by reference into the accompanying
prospectus. The consolidating selected financial data as of December 31, 2001,
2000 and 1999 and for the years ended December 31, 2000 and 1999 have been
derived from audited consolidated financial statements for those years, which
are not incorporated by reference into the accompanying prospectus, but which
are included with in our previous filings with the Securities and Exchange
Commission. You should read the table below in conjunction with "Management's
Discussion and Analysis of Financial Condition and Results of Operations" and
our consolidated financial statements and notes thereto incorporated by
reference in the accompanying prospectus.

     Acacia Research Corporation derived the Acacia Technologies group and
CombiMatrix group balance sheet data and statement of operations data from the
separate audited financial statements of the Acacia Technologies group and the
CombiMatrix group for the years ended December 31, 2003, 2002 and 2001, and the
table should be read in conjunction with the Acacia Research Corporation
consolidated financial statements and related notes thereto, incorporated by
reference into the accompanying prospectus, which include the separate audited
financial statements of our Acacia Technologies group and CombiMatrix group.

     The Acacia Research-Acacia Technologies common stock and the Acacia
Research-CombiMatrix common stock are intended to reflect the separate
performance of the respective divisions of Acacia Research Corporation, rather
than the performance of Acacia Research Corporation as a whole. The chief
mechanisms intended to cause the Acacia Research-Acacia Technologies common
stock and the Acacia Research-CombiMatrix common stock to reflect the financial
performance of the respective groups are provisions in our restated certificate
of incorporation and common stock policies governing dividends and distributions
to each class of stock, which specifically require the allocation of earnings to
each class based upon the performance of the two groups determined in accordance
with generally accepted accounting principles. Under these provisions, Acacia
Research Corporation factors the assets and liabilities and income or losses
attributable to the respective groups, determined as described under Item 7
"Management's Discussion and Analysis of Financial Condition and Results of
Operations - Critical Accounting Policies," (set forth in our latest Annual
Report on Form 10-K incorporated by reference in this prospectus supplement and
the accompanying prospectus) into the determination of the amounts available to
pay dividends, if any, on the shares issued for the respective groups and
require Acacia Research Corporation to exchange, redeem or distribute a dividend
on the stock of a group if all or substantially all of the assets allocated to
the respective group are sold to a third party.

     The Acacia Technologies group and the CombiMatrix group are not separate
legal entities. Holders of Acacia Research-Acacia Technologies stock and Acacia
Research-CombiMatrix stock are stockholders of Acacia Research Corporation. As a
result, stockholders continue to be subject to all of the risks of an investment
in Acacia Research Corporation and all of its businesses, assets and
liabilities. The assets that Acacia Research Corporation attributes to one group
could be subject to the liabilities of the other group.

                                      S-4


                                            CONSOLIDATING STATEMENT OF OPERATIONS DATA(4)
                                           (IN THOUSANDS, EXCEPT SHARE AND PER SHARE DATA)


                                                                             FOR THE YEARS ENDED DECEMBER 31,
                                                       -----------------------------------------------------------------------------
                                                            2003            2002            2001            2000            1999
                                                       -------------   -------------   -------------   -------------   -------------
                                                                                                        
REVENUES:
     Acacia Technologies group .....................   $        692    $         43    $     24,180    $         40    $        122
     CombiMatrix group .............................            456             839             456              17             144
                                                       -------------   -------------   -------------   -------------   -------------
     ACACIA RESEARCH CORPORATION ...................   $      1,148    $        882    $     24,636    $         57    $        266
                                                       =============   =============   =============   =============   =============
OPERATING (LOSS) INCOME
     Acacia Technologies group .....................   $     (6,013)   $     (9,865)   $      5,858    $    (12,606)   $     (4,955)
     CombiMatrix group .............................        (19,349)        (70,460)        (49,056)        (24,557)         (2,625)
                                                       -------------   -------------   -------------   -------------   -------------
     ACACIA RESEARCH CORPORATION ...................   $    (25,362)   $    (80,325)   $    (43,198)   $    (37,163)   $     (7,580)
                                                       =============   =============   =============   =============   =============
OTHER (EXPENSE) INCOME, NET:
     Acacia Technologies group .....................   $        408    $     (3,503)   $      2,111    $     (2,897)   $       (818)
     CombiMatrix group .............................            214             392           2,055           1,662            (224)
                                                       -------------   -------------   -------------   -------------   -------------
     ACACIA RESEARCH CORPORATION ...................   $        622    $     (3,111)   $      4,166    $     (1,235)   $     (1,042)
                                                       =============   =============   =============   =============   =============
(LOSS) INCOME FROM CONTINUING OPERATIONS BEFORE
   MINORITY INTERESTS:
     Acacia Technologies group .....................   $     (5,468)   $    (12,658)   $      7,034    $    (15,509)   $     (5,791)
     CombiMatrix group .............................        (18,999)        (69,921)        (46,846)        (22,816)         (2,851)
                                                       -------------   -------------   -------------   -------------   -------------
     ACACIA RESEARCH CORPORATION ...................   $    (24,467)   $    (82,579)   $    (39,812)   $    (38,325)   $     (8,642)
                                                       =============   =============   =============   =============   =============
MINORITY INTERESTS:
     Acacia Technologies group .....................   $         17    $        104    $     (1,277)   $        866    $        (27)
     CombiMatrix group .............................             30          23,702          18,817           8,300           1,248
                                                       -------------   -------------   -------------   -------------   -------------
     ACACIA RESEARCH CORPORATION ...................   $         47    $     23,806    $     17,540    $      9,166    $      1,221
                                                       =============   =============   =============   =============   =============
(LOSS) INCOME FROM CONTINUING OPERATIONS:
     Acacia Technologies group .....................   $     (5,451)   $    (12,554)   $      5,757    $    (14,643)   $     (5,818)
     CombiMatrix group .............................        (18,969)        (46,219)        (28,029)        (14,516)         (1,603)
                                                       -------------   -------------   -------------   -------------   -------------
     ACACIA RESEARCH CORPORATION ...................   $    (24,420)   $    (58,773)   $    (22,272)   $    (29,159)   $     (7,421)
                                                       =============   =============   =============   =============   =============
LOSS FROM DISCONTINUED OPERATIONS (1):
     Acacia Technologies group .....................   $         --    $       (200)   $         --    $     (9,554)   $       (776)
     CombiMatrix group .............................             --              --              --              --              --
                                                       -------------   -------------   -------------   -------------   -------------
     ACACIA RESEARCH CORPORATION ...................   $         --    $       (200)   $         --    $     (9,554)   $       (776)
                                                       =============   =============   =============   =============   =============
NET (LOSS) INCOME:
     Acacia Technologies group .....................   $     (5,451)   $    (12,754)   $      5,757    $    (24,197)   $     (6,594)
     CombiMatrix group .............................        (18,969)        (46,219)        (28,029)        (14,762)         (1,603)
                                                       -------------   -------------   -------------   -------------   -------------
     ACACIA RESEARCH CORPORATION ...................   $    (24,420)   $    (58,973)   $    (22,272)   $    (38,959)   $     (8,197)
                                                       =============   =============   =============   =============   =============

LOSS PER COMMON SHARE - BASIC AND DILUTED(5):
LOSS FROM CONTINUING OPERATIONS
     Acacia Research - Acacia Technologies stock ...   $      (0.28)   $      (0.64)   $         --    $         --    $         --
     Acacia Research - CombiMatrix stock ...........          (0.76)          (2.01)             --              --              --
     Acacia Research Corporation ...................             --              --           (1.16)          (1.78)          (0.59)
LOSS FROM DISCONTINUED OPERATIONS
     Acacia Research - Acacia Technologies stock ...   $         --    $      (0.01)   $         --    $         --    $         --
     Acacia Research - CombiMatrix stock ...........             --              --              --              --              --
     Acacia Research Corporation ...................             --              --              --           (0.58)          (0.06)
NET LOSS
     Acacia Research - Acacia Technologies stock ...   $      (0.28)   $      (0.65)   $         --    $         --    $         --
     Acacia Research - CombiMatrix stock ...........          (0.76)          (2.01)             --              --              --
     Acacia Research Corporation ...................             --              --           (1.16)          (2.38)          (0.65)
WEIGHTED AVERAGE NUMBER OF COMMON AND POTENTIAL
COMMON SHARES USED IN COMPUTATION OF LOSS PER
COMMON SHARE(2) (5):
BASIC AND DILUTED
     Acacia Research - Acacia Technologies stock ...     19,661,655      19,640,808              --              --              --
                                                       =============   =============   =============   =============   =============
     Acacia Research - CombiMatrix stock ...........     24,827,819      22,950,746              --              --              --
                                                       =============   =============   =============   =============   =============
     Acacia Research Corporation ...................             --              --      19,259,256      16,346,099      12,649,133
                                                       =============   =============   =============   =============   =============

                                                                 S-5



                                       CONSOLIDATING BALANCE SHEET DATA(4)
                                                 (IN THOUSANDS)


                                                                     AT DECEMBER 31,
                                          ----------------------------------------------------------------------
                                             2003           2002           2001           2000           1999
                                          ----------     ----------     ----------     ----------     ----------
                                                                                       
TOTAL ASSETS:
     Acacia Technologies group ......     $  39,978      $  47,212      $  62,926      $  37,062      $  49,788
     CombiMatrix group ..............        50,161         49,973         47,963         61,561          2,003
     Eliminations ...................           (99)          (114)           (30)          (107)            --
                                          ----------     ----------     ----------     ----------     ----------
     ACACIA RESEARCH CORPORATION ....     $  90,040      $  97,071      $ 110,859      $  98,516      $  51,791
                                          ==========     ==========     ==========     ==========     ==========
LONG-TERM INDEBTEDNESS:
     Acacia Technologies group ......     $      --      $      --      $      --      $      --      $      --
     CombiMatrix group ..............            --             --          1,845             --             --
                                          ----------     ----------     ----------     ----------     ----------
     ACACIA RESEARCH CORPORATION ....     $      --      $      --      $   1,845      $      --      $      --
                                          ==========     ==========     ==========     ==========     ==========
TOTAL LIABILITIES(3):
     Acacia Technologies group ......     $   4,188      $   5,183      $   5,723      $   5,075      $   1,304
     CombiMatrix group ..............        24,424         13,972         14,131         15,880            229
     Eliminations ...................           (99)          (114)           (30)          (107)           100
                                          ----------     ----------     ----------     ----------     ----------
     ACACIA RESEARCH CORPORATION ....     $  28,513      $  19,041      $  19,824      $  20,848      $   1,633
                                          ==========     ==========     ==========     ==========     ==========
MINORITY INTERESTS(3):
     Acacia Technologies group ......     $   1,127      $   1,487      $   2,194      $   2,012      $   3,992
     CombiMatrix group ..............            --            684         30,109         15,512            904
                                          ----------     ----------     ----------     ----------     ----------
     ACACIA RESEARCH CORPORATION ....     $   1,127      $   2,171      $  32,303      $  17,524      $   4,896
                                          ==========     ==========     ==========     ==========     ==========
REDEEMABLE STOCKHOLDERS' EQUITY:
     Acacia Technologies group ......     $  34,663      $  40,542      $  55,009      $  29,975      $  44,492
     CombiMatrix group ..............        25,737         35,317          3,723         30,169            770
                                          ----------     ----------     ----------     ----------     ----------
     ACACIA RESEARCH CORPORATION ....     $  60,400      $  75,859      $  58,732      $  60,144      $  45,262
                                          ==========     ==========     ==========     ==========     ==========


-------------------

(1)   On February 13, 2001, the board of directors of Soundbreak.com, one of our
      majority-owned subsidiaries, resolved to cease operations as of February
      15, 2001 and liquidate the remaining assets and liabilities of
      Soundbreak.com. Operating results in 1999 have been restated to present
      Soundbreak.com as discontinued operations. See Note 11 to the Acacia
      Research Corporation consolidated financial statements.

(2)   Potential common shares in 2003, 2002, 2001, 2000 and 1999 have been
      excluded from the per share calculations because the effect of their
      inclusion would be anti-dilutive. In addition, all share and per share
      information has been adjusted as appropriate for all periods presented to
      reflect a two-for-one stock split effected in March 1998 and a ten percent
      (10%) stock dividend distributed on December 5, 2001 for stockholders of
      record as of November 21, 2001.

(3)   Effective January 1, 2001, we changed our accounting policy for balance
      sheet classification of employee stock-based compensation resulting from
      awards in consolidated subsidiaries. As a result, effective January 1,
      2001, amortized non-cash stock compensation charges related to subsidiary
      stock options are included in minority interests in our consolidated
      balance sheet. Prior to the change in accounting policy, amortized
      non-cash stock compensation charges related to subsidiary stock options
      were reflected as "accrued stock compensation" in consolidated
      liabilities. There is no impact on previous consolidated statements of
      operations as a result of this change in accounting policy.

(4)   The management and allocation policies applicable to the preparation of
      the financial statements of the Acacia Technologies group and the
      CombiMatrix group and as a result, to the measurement by which dividends
      or performance are determined for each group, may be modified or
      rescinded, or additional policies may be adopted, at the sole discretion
      of the Acacia Research Board at any time without approval of the
      stockholders. The Acacia Technologies group's and the CombiMatrix group's
      financial statements reflect the application of the management and
      allocation policies adopted by the Acacia Research Corporation's board of
      directors to various corporate activities. Management has no plans to
      change allocation methods or the composition of the groups. Refer to Item
      7 "Management's Discussion and Analysis of Financial Condition - Critical
      Accounting Policies" for a description of allocation policies applied.

(5)   The 2002 share and per share information gives effect to the
      recapitalization transaction described elsewhere herein as of January 1,
      2002. Historical share and per share information for the Acacia
      Research-Acacia Technologies stock and Acacia Research-CombiMatrix stock
      is not presented as these classes of securities were not part of Acacia
      Research Corporation's capital structure during 2001 and prior periods.

                                       S-6


                        FACTORS AFFECTING COMPARABILITY:

o    The Acacia Technologies group revenues reflected in 1999 primarily relate
     to capital management fee income, including performance fee income,
     recorded by the Acacia Capital Management division. During the fourth
     quarter of 1999, Acacia Research Corporation closed its Acacia Capital
     Management division. Acacia Capital Management was a general partner in two
     private investment partnerships and was an investment advisor to two
     offshore private investment corporations.

o    In the fourth quarter of 2000, Acacia Research Corporation recorded $1.0
     million in write-offs of other early stage investments and $2.6 million in
     write-offs of equity investments, attributed to the Acacia Technologies
     group.

o    During the year ended December 31, 2000, CombiMatrix Corporation recorded
     deferred non-cash stock compensation charges aggregating approximately
     $53.8 million in connection with the granting of stock options. Deferred
     non-cash stock compensation charges are being amortized by the CombiMatrix
     group over the respective option grant vesting periods, which range from
     one to four years. Non-cash stock compensation charges totaled $1.7
     million, $6.4 million and $20.0 million in 2003, 2002 and 2001,
     respectively. Non-cash stock compensation charges were not significant in
     prior periods.

o    In connection with Acacia Research Corporation's increased focus on the
     media technologies and life sciences sectors, certain of Acacia Research
     Corporation's businesses allocated to the Acacia Technologies group ceased
     operations and certain investments were written off in 2000. As a result,
     marketing, general and administrative costs related to salaries, benefits,
     consulting, legal and other professional costs were significantly reduced
     in 2001.

o    In June 2003 and September 2002, Acacia Research Corporation recorded
     impairment charges of $207,000 and $2.7 million, respectively, for an
     other-than-temporary decline in the fair value of a cost method investment,
     attributed to the Acacia Technologies group.

o    On December 13, 2002, Acacia Research Corporation increased its
     consolidated ownership interest in CombiMatrix Corporation from 48% to
     100%. $17.2 million of the total purchase price of $46.0 million was
     attributed to acquired in-process research and development, or IPR&D, and
     was charged to expense in the consolidated statement of operations and
     comprehensive loss for the year ended December 31, 2002. Amounts allocated
     to IPR&D have been attributed to the CombiMatrix group.

o    On September 30, 2002, CombiMatrix Corporation and Dr. Donald Montgomery,
     an officer and stockholder of CombiMatrix Corporation, entered into a
     settlement agreement with Nanogen to settle all pending litigation between
     the parties. In addition to other terms of the settlement agreement,
     CombiMatrix Corporation agreed to pay Nanogen $1.0 million and issued
     4,016,346 shares, or 17.5% of its outstanding shares post issuance, to
     Nanogen. The $1.0 million in payments have been expensed in the
     consolidated statement of operations for the year ended December 31, 2002
     under "legal settlement charges." The issuance of the CombiMatrix
     Corporation common shares in settlement of the litigation with Nanogen has
     been accounted for as a nonmonetary transaction. Accordingly, included in
     "legal settlement charges" in the consolidated statements of operations for
     the year ended December 31, 2002 is a charge in the amount of $17.5 million
     based on the fair value of the CombiMatrix Corporation common shares issued
     to Nanogen. Amounts related to the settlement have been attributed to the
     CombiMatrix group.

                                      S-7


                                   MANAGEMENT

     The following is biographical information for our officers and members of
our board of directors:

NAME                            AGE                   POSITION
----                            ---                   --------
EXECUTIVE OFFICERS
Paul R. Ryan                     58    Chairman and Chief Executive Officer
Robert L. Harris, II             45    President and Director
Amit Kumar, Ph.D.                39    Chief Executive Officer and President of
                                       CombiMatrix Corporation, and Director
Clayton J. Haynes                34    Chief Financial Officer, Treasurer and
                                       Senior Vice President, Finance
Robert A. Berman                 41    Executive Vice President, General Counsel
                                       and Secretary

DIRECTORS
Thomas B. Akin                   51    Director
Fred A. de Boom                  68    Director
Edward W. Frykman                67    Director
G. Louis Graziadio, III          54    Director
Rigdon Currie                    73    Director

     PAUL R. RYAN has served as a director since August 1995, as Chief Executive
Officer since January 1997 and as Chairman since April 2000. He also served as
President of the Company from January 1997 until July 2000. Prior to being named
Chief Executive Officer, he was Executive Vice President and Chief Investment
Officer of the Company from 1996 through 1997 and Vice President, Capital
Management, of the Company from 1995 through 1996. He was formerly co-founder
and general partner of the American Health Care Fund, L.P., held positions with
Young & Rubicam, Ogilvy & Mather, and Merrill Lynch and was a private venture
capital investor. Mr. Ryan holds a B.S. from Cornell University and attended the
New York University Graduate School of Business.

     ROBERT L. HARRIS, II has served as a director since April 2000 and as
President since July 2000. Mr. Harris was previously the President and Director
of Entertainment Properties Trust from 1997 to July 2000. Mr. Harris founded
Entertainment Properties Trust, a publicly-traded company that purchases real
estate from major entertainment companies. Mr. Harris led the International
Division and served as Senior Vice President of AMC Entertainment from 1993 to
1997, and served as President of Carlton Browne and Company, Inc., a holding
company and trust with assets in real estate, insurance and financial services,
from 1984 to 1992.

     AMIT KUMAR, PH.D. has served as a director since January 2003. Dr. Kumar
joined Acacia Research Corporation in July 2000 as Senior Vice President of Life
Sciences. Dr. Kumar was appointed to the position of Chief Executive Officer and
President of CombiMatrix Corporation in September 2001. From 1999 to 2000, Dr.
Kumar was CEO and President of Signature Biosciences, a genomic, proteomic, and
drug discovery company. From 1998 to 1999, he was an Entrepreneur in Residence
at Oak Investment Partners, specializing in emerging life science and
biotechnology companies. Dr. Kumar held the position of Senior Manager at IDEXX
Laboratories, and was Head of Research and Development at Idetek Corporation
from 1995 to 1998. He held the position of Sr. Scientist at Idetek Corporation
from 1994-1995. Dr. Kumar is a director of Digital Campaigns, Inc., a private
company, and is a member of the Scientific Advisory Board of BioProcessors Inc.,
a private company. Dr. Kumar received his bachelor's degree from Occidental
College in 1986, his Ph.D. from the California Institute of Technology in 1991,
and completed his Post-Doctorate Fellowship at Harvard University in 1993.

     CLAYTON J. HAYNES joined the Company in April 2001 as Treasurer and Senior
Vice President, Finance. In November 2001, Mr. Haynes was appointed Chief
Financial Officer of the Company. From 1992 to March 2001, Mr. Haynes was
employed by PricewaterhouseCoopers LLP, ultimately serving as a Manager in the
Audit and Business Advisory Services practice. Mr. Haynes received a B.A. from
the University of California at Los Angeles, is a Certified Public Accountant
and is a member of the American Institute of Certified Public Accountants.

     ROBERT A. BERMAN joined the Company in 2000 and was named Senior Vice
President and General Counsel in February 2001. In November 2003, Mr. Berman was
appointed Executive Vice President, Business Development. Mr. Berman held the
position of Director of New Business Development at National Media Corporation
from 1997 to 1999 and at QVC from 1993 to 1997. He practiced law at the
Philadelphia law firm of Blank, Rome, Comsikey and McCauley from 1989 to 1993.
Mr. Berman received a B.S. from the University of Pennsylvania's Wharton School,
and a J.D. from Northwestern Law School.

                                      S-8


     THOMAS B. AKIN has served as a director since May 1998. Mr. Akin serves as
the managing partner of Talkot Capital, LLC. In that capacity Mr. Akin is the
general partner of Talkot Crossover Fund and Talkot Capital IV, LLC. Mr. Akin
previously worked for Merrill Lynch and Salomon Brothers in various roles in
institutional sales. Mr. Akin serves as the Chairman of the Board of Dynex
Capital, Inc. and as a director and member of the Audit Committee of ADX
Corporation. Mr. Akin holds a B.A. from the University of California at Santa
Cruz and an M.B.A. in finance from the University of California at Los Angeles.

     FRED A. DE BOOM has served as a director since February 1995. Mr. de Boom
has been a principal in Sonfad Associates since 1995. Sonfad Associates is a Los
Angeles-based investment banking firm that is involved in mergers and
acquisitions, private debt and equity placements, strategic and financial
business planning, leveraged buy-outs and ESOP funding, bank debt refinance,
asset based and lease financing, and equity for debt restructuring. Previously,
he was employed as a Vice President of Tokai Bank for five years and as a Vice
President of Union Bank for eight years. Mr. de Boom received his B.A. degree
from Michigan State University and his M.B.A. degree from the University of
Southern California.

     EDWARD W. FRYKMAN has served as a director since April 1996. Mr. Frykman
has been an Account Executive with Crowell, Weedon & Co. since 1992. Previously,
Mr. Frykman served as Senior Vice President of L.H. Friend & Co. Both Crowell,
Weedon & Co. and L.H. Friend & Co. are investment brokerage firms located in
Southern California. In addition, Mr. Frykman was a Senior Account Executive
with Shearson Lehman Hutton where he served as the Manager of the Los Angeles
Regional Retail Office. Mr. Frykman serves as a director of Arrowhead Research
Corp.

     G. LOUIS GRAZIADIO, III has been a director since February 2002. Mr.
Graziadio has held the positions of Chairman and Chief Executive Officer of
Second Southern Corp., the managing partner of Ginarra Partners, L.L.C., a
California company engaged in a wide range of investment activities and business
ventures, since 1990. He also serves as Chairman and Chief Executive Officer of
Boss Holdings, Inc.

     RIGDON CURRIE has been a director since January 2003. Mr. Currie is a
director and a member of the Compensation Committee of ESP, Inc., which develops
software for managing industrial environmental issues; Chairman of the Board of
Opportunity Capital Corporation, a private venture capital firm focused on
minority business; and a director of W3 Commerce, Inc., a private software firm
focused on Internet commerce traffic generation. Mr. Currie received a B.S.I.E.
from the Georgia Institute of Technology and an M.B.A. from Harvard Business
School.

                                      S-9



                                                    THE OFFERING


                                                          
Acacia Research-CombiMatrix common stock offered..........   3,000,000 shares

Acacia Research-CombiMatrix common stock to be outstanding
after this offering ......................................   29,328,122 shares

Acacia Research-Acacia Technologies common stock offered..   0 shares

Acacia Research-Acacia Technologies common stock to be
outstanding after this offering ..........................   19,739,984 shares

Use of Proceeds...........................................   We intend to use the net proceeds from the sale of the
                                                             securities offered by this prospectus and the related
                                                             accompanying prospectus supplement to provide working
                                                             capital for our business, including our subsidiaries.

Nasdaq National Market symbol.............................   CBMX: ACTG


     The information above is based on 26,328,122 shares of Acacia
Research-CombiMatrix common stock and 19,739,984 shares of Acacia
Research-Acacia Technologies common stock outstanding as of December 31, 2003,
and excludes:

     o    6,616,740 shares of Acacia Research-CombiMatrix common stock that may
          be issued upon the exercise of outstanding options granted under our
          2002 CombiMatrix Stock Incentive Plan at a weighted average exercise
          price of $7.28 per share as of December 31, 2003.

     o    2,208,443 shares reserved for issuance under our 2002 CombiMatrix
          Stock Incentive Plan as of December 31, 2003. The share reserve under
          the 2002 CombiMatrix Stock Incentive Plan automatically increases on
          the first trading day in January each calendar year by an amount equal
          to three percent (3%) of the total number of shares of our Acacia
          Research-CombiMatrix common stock outstanding on the last trading day
          of December in the prior calendar year, but in no event will this
          annual increase exceed 600,000 shares and in no event will the total
          number of common stock in the share reserve (as adjusted for all such
          annual increases) exceed twenty million shares.

     o    1,045,000 shares of Acacia Research-CombiMatrix common stock that may
          be issued upon the exercise of outstanding warrants at a per share
          exercise price of $2.75, which warrants are exercisable through May
          2008.

     o    1,240,000 shares of Acacia Research-Acacia Technologies common stock
          that were issuable upon the exercise of warrants at a per share
          exercise price of $13.23. These warrants expired unexercised in
          January 2004.

     o    692,000 shares of Acacia Research-CombiMatrix common stock that were
          issuable upon the exercise of warrants at a per share exercise price
          of $10.50. These warrants expired unexercised in January 2004.

     o    5,138,630 shares of Acacia Research-Acacia Technologies common stock
          that may be issued upon the exercise of outstanding options granted
          under our 2002 Acacia Technologies Stock Incentive Plan at a weighted
          average exercise price of $8.29 per share as of December 31, 2003.

     o    470,049 shares reserved for issuance under our 2002 Acacia
          Technologies Stock Incentive Plan as of December 31, 2003. The share
          reserve under the 2002 Acacia Technologies Stock Incentive Plan
          automatically increases on the first trading day in January each
          calendar year by an amount equal to three percent (3%) of the total
          number of shares of our Acacia Research-Acacia Technologies common
          stock outstanding on the last trading day of December in the prior
          calendar year, but in no event will this annual increase exceed
          500,000 shares and in no event will the total number of common stock
          in the share reserve (as adjusted for all such annual increases)
          exceed twenty million shares.

     To the extent that any of outstanding options are exercised, new options
are issued under our stock incentive plans or we issue additional shares of
common stock in the future, there will be further dilution to new investors.

                           __________________________

     Our address is 500 Newport Center Drive, 7th Floor, Newport Beach,
California 92660, and our telephone number is (949) 480-8300.

                                      S-10


                                 USE OF PROCEEDS

     We estimate that the net proceeds we will receive from this offering will
be approximately $13,605,000 million, after deducting the placement agent fees
and estimated offering expenses. We will retain broad discretion over the use of
the net proceeds from the sale of our Acacia Research-CombiMatrix common stock
offered hereby. We currently anticipate using the net proceeds from the sale of
our Acacia Research-CombiMatrix common stock hereby primarily for working
capital for our CombiMatrix group, including the CombiMatrix group's
subsidiaries.

     The amounts and timing of the CombiMatrix group's expenditures may vary
significantly depending on numerous factors, such as the progress of our
research and development efforts, technological advances and the competitive
environment for our products. We may also use a portion of the net proceeds to
acquire or invest in businesses complementary to the CombiMatrix group's
business, products and technologies. Although we have no specific arrangements
with respect to acquisitions, we evaluate acquisition opportunities and engage
in related discussions from time to time.

                                      S-11


                                    DILUTION

     Our net tangible book value on December 31, 2003 was as follows:



                                                             SHARES OF       NET TANGIBLE
                                       NET TANGIBLE         COMMON STOCK      BOOK VALUE
                                       BOOK VALUE(1)        OUTSTANDING       PURCHASE(4)
                                       -------------        -----------       -----------
                                                                    
     CombiMatrix group                  (3,804,987)        26,328,122 (2)       (0.14)

     Acacia Technologies group          30,448,742         19,739,984 (3)        1.54

     Acacia Research Consolidated       26,643,755         N/A                   N/A


--------------------------------------------------------------------------------

     (1)  Represents Net Tangible Book Value as of December 31, 2003. This Table
          should be read in connection with the selected financial data
          beginning on page S-4.

     (2)  Represents shares of AR-CombiMatrix common stock, which is intended to
          reflect the performance of Acacia Research Corporation's CombiMatrix
          group, outstanding on December 31, 2003.

     (3)  Represents shares of AR-Acacia Technologies common stock, which is
          intended to reflect the performance of Acacia Research Corporation's
          Acacia Technologies group, outstanding on December 31, 2003.

     (4)  Net tangible book value per share on December 31, 2003 is determined
          by dividing the net tangible book value, which consists of tangible
          assets less total liabilities, for the CombiMatrix group and the
          Acacia Technologies group, by the number of shares of AR-CombiMatix
          and AR-Acacia Technologies common stock, respectively, outstanding on
          that date. Holders of Acacia Research-CombiMatrix common stock,
          however, are common stockholders of Acacia Research Corporation and
          are subject to all of the risks of an equity investment in Acacia
          Research Corporation and all of its businesses, assets and
          liabilities.

     Without taking into account any other changes in the net tangible book
value for the CombiMatrix group after December 31, 2003, other than to give
effect to our receipt of the estimated net proceeds from the sale of the maximum
number of shares issuable in this offering (3,000,000 shares) at an offering
price of $5.00 per share, less the fees due to the placement agent and our
estimated offering expenses, the net tangible book value of the CombiMatrix
group as of December 31, 2003, after giving effect to the items above, would
have been approximately $9.8 million, or $0.33 per share. This represents an
immediate increase in the net tangible book value of $0.47 per share to existing
holders of Acacia Research-CombiMatrix common stock and an immediate dilution of
$4.67 per share to new investors. The following table illustrates this per share
dilution:



                                                                                  
     Offering price per share................................................        $ 5.00
                                                                                 ---------------

        Net tangible book value per share as of December 31, 2003............        $(0.14)
                                                                                 ---------------

        Increase in net tangible book value per share attributable to the
        offering.............................................................        $ 0.47
                                                                                 ---------------

     Pro forma net tangible book value per share as of December 31, 2003,
     after giving effect to the offering.....................................        $ 0.33
                                                                                 ---------------

     Dilution per share to new investors in the offering.....................        $ 4.67
                                                                                 ---------------


          The tables above are based on 26,328,122 shares of Acacia
Research-CombiMatrix common stock and 19,739,984 shares of Acacia
Research-Acacia Technologies common stock outstanding as of December 31, 2003,
and exclude the following shares of common stock that may be issued upon the
exercise of outstanding options granted and shares reserved for issuance under
our 2002 CombiMatrix Stock Incentive Plan and our 2002 Acacia Technologies Stock
Incentive Plan, as of December 31, 2003:

     o    6,616,740 shares of Acacia Research-CombiMatrix common stock that may
          be issued upon the exercise of outstanding options granted under our
          2002 CombiMatrix Stock Incentive Plan at a weighted average exercise
          price of $7.28 per share as of December 31, 2003.

                                      S-12


     o    2,208,443 shares reserved for issuance under our 2002 CombiMatrix
          Stock Incentive Plan as of December 31, 2003. The share reserve under
          the 2002 CombiMatrix Stock Incentive Plan automatically increases on
          the first trading day in January each calendar year by an amount equal
          to three percent (3%) of the total number of shares of our Acacia
          Research-CombiMatrix common stock outstanding on the last trading day
          of December in the prior calendar year, but in no event will this
          annual increase exceed 600,000 shares and in no event will the total
          number of common stock in the share reserve (as adjusted for all such
          annual increases) exceed twenty million shares.

     o    1,045,000 shares of Acacia Research-CombiMatrix common stock that may
          be issued upon the exercise of outstanding warrants at a per share
          exercise price of $2.75, which warrants are exercisable through May
          2008.

     o    1,240,000 shares of Acacia Research-Acacia Technologies common stock
          that were issuable upon the exercise of warrants at a per share
          exercise price of $13.23. These warrants expired unexercised in
          January 2004.

     o    692,000 shares of Acacia Research-CombiMatrix common stock that were
          issuable upon the exercise of warrants at a per share exercise price
          of $10.50. These warrants expired unexercised in January 2004.

     o    5,138,630 shares of Acacia Research-Acacia Technologies common stock
          that may be issued upon the exercise of outstanding options granted
          under our 2002 Acacia Technologies Stock Incentive Plan at a weighted
          average exercise price of $8.29 per share as of December 31, 2003.

     o    470,049 shares reserved for issuance under our 2002 Acacia
          Technologies Stock Incentive Plan as of December 31, 2003. The share
          reserve under the 2002 Acacia Technologies Stock Incentive Plan
          automatically increases on the first trading day in January each
          calendar year by an amount equal to three percent (3%) of the total
          number of shares of our Acacia Research-Acacia Technologies common
          stock outstanding on the last trading day of December in the prior
          calendar year, but in no event will this annual increase exceed
          500,000 shares and in no event will the total number of common stock
          in the share reserve (as adjusted for all such annual increases)
          exceed twenty million shares.

     To the extent that any of outstanding options are exercised, new options
are issued under our stock incentive plans or we issue additional shares of
common stock in the future, there will be further dilution to new investors.

                                      S-13


                              PLAN OF DISTRIBUTION

     We are offering the shares of our Acacia Research-CombiMatrix common stock
through two placement agents. Subject to the terms and conditions contained in
the placement agency agreement dated April 13, 2004, Thomas Weisel Partners LLC
and Brean Murray & Co., Inc. have agreed to act as placement agents for the sale
of up to 3,000,000 shares of our Acacia Research-CombiMatrix common stock. The
placement agents are not purchasing or selling any shares by this prospectus
supplement or accompanying prospectus, nor are they required to purchase or
arrange the purchase or sale of any specific number or dollar amount of shares,
but they have agreed to use best efforts to arrange for the sale of all
3,000,000 shares.

     The placement agency agreement provides that the obligations of the
placement agents and the investors are subject to certain conditions precedent,
including the absence of any material adverse change in our business and the
receipt of certain opinions, letters and certificates from our counsel, our
independent auditors and us.

     The shares of Acacia Research-CombiMatrix common stock sold in this
offering will be listed on the Nasdaq National Market under the symbol "CBMX".
We expect that the shares of Acacia Research-CombiMatrix common stock will be
delivered only in book-entry form through The Depository Trust Company, New
York, New York on or about April 15, 2004.

     It is possible that not all of the shares of our Acacia
Research-CombiMatrix common stock offered pursuant to this prospectus supplement
will be sold at the closing, in which case our net proceeds would be reduced.

     The placement agents' compensation for this offering will consist of a
placement agent fee and reimbursement of offering expenses described below. We
will pay the placement agent fees equal to (i) 8% of the first $5,000,000 in
gross proceeds received by us in the offering, (ii) 7% of the next $5,000,000 in
gross proceeds received by us in the offering, and (iii) 6% of all additional
gross proceeds received by us in the offering. Brean Murray & Co. will receive
15% of the aggregate placement fees and the remainder of the placement fees will
be paid to Thomas Weisel Partners LLC. However, no compensation will be payable
to the placement agents for sales of shares of our Acacia Research-CombiMatrix
common stock to strategic investors purchasing stock in connection with entering
into license, joint venture, partnership or other related agreements with us.
The estimated offering expenses payable by us, in addition to the placement
agent's fee, are approximately $345,000, which includes legal, accounting and
printing costs and various other fees associated with registering and listing
the shares of Acacia Research-CombiMatrix common stock. After deducting certain
fees due to the placement agent and our estimated offering expenses, we expect
the net proceeds from this offering to be up to approximately $13.6 million.

     The following table shows the per unit and total placement fees payable to
Thomas Weisel Partners LLC and Brean Murray & Co. in connection with the sale of
shares offered pursuant to this prospectus supplement and the accompanying
prospectus.
                                                     Per Share           Total
                                                     ---------           -----
Thomas Weisel Partners LLC......................       $0.30           $893,000
Brean Murray & Co...............................       $0.05           $157,000
Total...........................................       $0.35         $1,050,000

     We have agreed to indemnify the placement agent against certain
liabilities, including liabilities under the Securities Act of 1933, as amended,
and liabilities arising from breaches of representations and warranties
contained in the placement agency agreement. We have also agreed to contribute
to payments the placement agent may be required to make in respect of such
liabilities.

     We have agreed to certain lock-up provisions with regard to future sales of
our Acacia Research-CombiMatrix common stock for a period of 30 days after the
offering as set forth in the placement agency agreement.

     The placement agency agreement with Thomas Weisel Partners LLC is included
as an exhibit to our Current Report on Form 8-K that will be filed with the
Securities and Exchange Commission in connection with the consummation of this
offering.

     The transfer agent for our common stock is U.S. Stock Transfer Corporation.

                                      S-14


                                  LEGAL MATTERS

     The validity of our securities offered in this prospectus supplement and
accompanying prospectus will be passed upon for us by Allen Matkins Leck Gamble
& Mallory LLP, Century City, California. Certain legal matters relating to this
offering will be passed upon for the placement agent by Wilson Sonsini Goodrich
& Rosati, New York City, New York.

                                      S-15


                                                FILED PURSUANT TO RULE 424(b)(3)
                                                     REGISTRATION NO. 333-112885

PROSPECTUS

                                   $50,000,000


                                     ACACIA
                                    RESEARCH
                                  CORPORATION


                           ACACIA RESEARCH CORPORATION

                    ACACIA RESEARCH-COMBIMATRIX COMMON STOCK
                ACACIA RESEARCH-ACACIA TECHNOLOGIES COMMON STOCK
                                    WARRANTS
                           __________________________

     By this prospectus, we may offer, from time to time:

     o    shares of our Acacia Research-CombiMatrix common stock;

     o    shares of our Acacia Research-Acacia Technologies common stock;

     o    warrants to purchase shares of our Acacia Research-CombiMatrix common
          stock and our Acacia Research-Acacia Technologies common stock; or

     o    any combination of the foregoing.

     We will provide specific terms of each issuance of these securities in
supplements to this prospectus. You should read this prospectus and any
supplement carefully before you decide to invest.

     This prospectus may not be used to consummate sales of these securities
unless it is accompanied by a prospectus supplement.

     Our Acacia Research-CombiMatrix common stock is traded on the Nasdaq
National Market under the ticker symbol "CBMX." On March 16, 2004, the last
reported sales price of our Acacia Research-CombiMatrix common stock was $6.01
per share.

     Our Acacia Research-Acacia Technologies common stock is traded on the
Nasdaq National Market under the ticker symbol "ACTG." On March 16, 2004, the
last reported sales price of our Acacia Research-Acacia Technologies common
stock was $6.54 per share.

     We may sell these securities to or through underwriters, dealers or agents,
or we may sell the securities directly to investors on our own behalf.

     INVESTING IN OUR SECURITIES INVOLVES A HIGH DEGREE OF RISK. YOU SHOULD
CAREFULLY CONSIDER THE INFORMATION UNDER THE HEADING "RISK FACTORS" BEGINNING ON
PAGE 2 OF THIS PROSPECTUS BEFORE BUYING ANY OF THE SECURITIES OFFERED HEREBY.

                           __________________________

     NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES, OR DETERMINED IF
THIS PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.


                  THE DATE OF THIS PROSPECTUS IS MARCH 17, 2004



         YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN OR INCORPORATED BY
REFERENCE INTO THIS PROSPECTUS. WE HAVE NOT AUTHORIZED ANY OTHER PERSON TO
PROVIDE YOU WITH DIFFERENT INFORMATION. IF ANYONE PROVIDES YOU WITH DIFFERENT OR
INCONSISTENT INFORMATION, YOU SHOULD NOT RELY ON IT. THE INFORMATION IN THIS
PROSPECTUS IS CURRENT AS OF THE DATE OF THIS PROSPECTUS. OUR BUSINESS, FINANCIAL
CONDITION, RESULTS OF OPERATIONS AND PROSPECTS MAY HAVE CHANGED SINCE THAT DATE.


                                TABLE OF CONTENTS


About This Prospectus.........................................................1
Our Company...................................................................1
Risk Factors..................................................................2
Forward-Looking Statements...................................................22
Use Of Proceeds..............................................................22
Description of our Capital Stock.............................................23
Description of Warrants......................................................29
Plan of Distribution.........................................................30
Experts  31
Legal Matters................................................................31
Where You Can Find More Information..........................................31
Information Incorporated By Reference........................................32

                                      (i)


                              ABOUT THIS PROSPECTUS

         This prospectus is part of a registration statement that we filed with
the Securities and Exchange Commission, or SEC, using a "shelf" registration
process. Under this process, we may offer and sell any combination of Acacia
Research-CombiMatrix common stock ("AR-CombiMatrix Stock"), Acacia
Research-Acacia Technologies common stock ("AR-Acacia Technologies Stock") and
warrants to purchase our AR-CombiMatrix Stock or our AR-Acacia Technologies
stock in one or more offerings for total proceeds of up to $50,000,000. This
prospectus provides you with a general description of the securities we may
offer. Each time we offer to sell securities, we will provide a supplement to
this prospectus that will contain specific information about the terms of that
offering. The prospectus supplement may also add, update or change information
contained in this prospectus. It is important for you to consider the
information contained in this prospectus and any prospectus supplement together
with additional information described under the heading "Where You Can Find More
Information."

                                   OUR COMPANY

OUR BUSINESS

         Acacia Research develops, acquires and licenses enabling technologies
for the life sciences and media technologies sectors, which comprise the two
business groups of Acacia Research.

         Our life sciences business, referred to as the "CombiMatrix group," is
comprised of our wholly owned subsidiaries, CombiMatrix Corporation, CombiMatrix
Corporation's majority owned subsidiary, Advanced Material Sciences, Inc., and
CombiMatrix Corporation's wholly owned subsidiary, CombiMatrix KK. CombiMatrix
Corporation is a life sciences technology company with a proprietary system for
rapid, cost competitive creation of DNA and other compounds on a programmable
semiconductor chip. This proprietary technology has applications in the areas of
genomics, proteomics, biosensors, drug discovery, drug development, diagnostics,
combinatorial chemistry, material sciences and nanotechnology.

         Our media technologies business, referred to as the "Acacia
Technologies group," is primarily comprised of our interests in two wholly owned
media technologies subsidiaries: Acacia Media Technologies Corporation and
Soundview Technologies, Inc. The Acacia Technologies group owns patented digital
media transmission, or DMT, technology enabling the digitization, encryption,
storage, transmission, receipt and playback of digital content. The DMT
technology is protected by five United States and 31 foreign patents. The DMT
technology is utilized by a variety of companies, including cable companies,
hotel in-room entertainment companies, Internet movie companies, Internet music
companies, on-line adult entertainment companies, on-line learning companies and
other companies that stream audio or audio/video content. The Acacia
Technologies group's United States DMT patents expire in 2011 and its
international DMT patents expire in 2012. The Acacia Technologies group also
owns technology known as the V-chip. The V-chip was adopted by manufacturers of
televisions sold in the United States to provide blocking of certain programming
based upon its content rating code, in compliance with the Telecommunications
Act of 1996. The V-chip technology was protected by U.S. Patent No. 4,554,584,
which expired in July 2003.

GENERAL INFORMATION

         We were incorporated on January 25, 1993 under the laws of the State of
California. In December 1999, we changed our state of incorporation from
California to Delaware. Our principal executive office is located at 500 Newport
Center Drive, 7th Floor, Newport Beach, California 92660. Our telephone number
is (949) 480-8300.

                                       1


                                  RISK FACTORS

         AN INVESTMENT IN OUR STOCK INVOLVES A NUMBER OF RISKS. BEFORE MAKING A
DECISION TO PURCHASE OUR SECURITIES, YOU SHOULD CAREFULLY CONSIDER ALL OF THE
RISKS DESCRIBED IN THIS PROSPECTUS. IF ANY OF THE RISKS DISCUSSED IN THIS
PROSPECTUS ACTUALLY OCCUR, OUR BUSINESS, FINANCIAL CONDITION AND RESULTS OF
OPERATIONS COULD BE MATERIALLY ADVERSELY AFFECTED. IF THIS WERE TO OCCUR, THE
TRADING PRICE OF OUR SECURITIES COULD DECLINE SIGNIFICANTLY AND YOU MAY LOSE ALL
OR PART OF YOUR INVESTMENT.

                                  GENERAL RISKS

THE CONTINUING WORLDWIDE ECONOMIC SLOWDOWN AND RELATED UNCERTAINTIES MAY
CONTINUE TO ADVERSELY IMPACT OUR REVENUES AND OPERATING RESULTS.

         Slower economic activity, concerns about inflation, decreased consumer
confidence, reduced corporate profits and capital spending, adverse business
conditions and liquidity concerns in the technology and biotechnology and
related industries, the lingering effects of the war in Iraq, recent
international conflicts and the events of September 11, 2001 and other terrorist
and military activity have resulted in a continuing downturn in worldwide
economic conditions. We cannot predict the timing, strength and duration of any
economic recovery in our industries. These conditions make it extremely
difficult for us to accurately forecast and plan future business activities. We
cannot predict the timing, strength and duration of any economic recovery,
worldwide or in our markets. If such conditions continue or worsen, our
business, financial condition and results of operations will likely be
materially and adversely affected.

BECAUSE OUR BUSINESS OPERATIONS ARE SUBJECT TO MANY INHERENT AND UNCONTROLLABLE
RISKS, WE MAY NOT SUCCEED.

         We have significant economic interests in our subsidiary companies. Our
business operations are subject to numerous risks, challenges, expenses and
uncertainties inherent in the establishment of new business enterprises. Many of
these risks and challenges are subject to outside influences over which we have
no control, including:

         o        our subsidiary companies' products and services face uncertain
                  market acceptance;

         o        technological advances may make our subsidiary companies'
                  products and services obsolete or less competitive;

         o        competition is intense in the industries in which our
                  subsidiaries do business;

         o        increases in operating costs, including costs for supplies,
                  personnel and equipment;

         o        the availability and cost of capital;

         o        general economic conditions; and

         o        governmental regulation that excessively restricts our
                  subsidiary companies' businesses.

         We cannot assure you that our subsidiary companies will be able to
market any product or service on a large commercial scale, that our subsidiary
companies will ever achieve or maintain profitable operations or that they, or
we, will be able to remain in business.

WE HAVE A HISTORY OF LOSSES AND EXPECT TO INCUR ADDITIONAL LOSSES IN THE FUTURE.

         We have sustained substantial losses since our inception resulting in
an accumulated deficit, as of December 31, 2003, of $183.4 million on a
consolidated basis. We may never become profitable or if we do, we may never be
able to sustain profitability. We expect to incur significant research and
development, marketing, general and administrative expenses. As a result, we
expect to incur significant losses for the foreseeable future.

                                       2


OUR STOCK PRICE MAY BE VOLATILE, WHICH COULD RESULT IN SUBSTANTIAL LOSSES FOR
INVESTORS IN OUR SECURITIES.

         The stock markets in general, and the markets for technology stocks in
particular, have experienced extreme volatility that has often been unrelated to
the operating performance of particular companies. These broad market
fluctuations may adversely affect the trading price of our two classes of common
stock.

         The market prices of our securities may also fluctuate significantly in
response to the following factors, some of which are beyond our control:

         o        variations in our quarterly operating results;

         o        changes in management's or securities analysts' estimates of
                  our financial performance;

         o        changes in market valuations of similar companies;

         o        announcements by us or our competitors of significant
                  contracts, acquisitions, strategic partnerships, joint
                  ventures, capital commitments, new products or product
                  enhancements;

         o        failure to complete significant transactions; and

         o        additions or departures of key personnel.

BECAUSE CERTAIN OF OUR SUBSIDIARY COMPANIES MAY NOT GENERATE ANY SIGNIFICANT
REVENUES, AND OPERATING RESULTS FROM OUR SUBSIDIARY COMPANIES MAY FLUCTUATE
SIGNIFICANTLY, OUR OWN OPERATING RESULTS MAY BE NEGATIVELY AFFECTED.

         Our operating results may be materially impacted by the operating
results of our subsidiary companies. We cannot assure that these companies will
be able to meet their anticipated working capital needs to develop their
products and services. If they fail to properly develop these products and
services, they will be unable to generate meaningful product sales. We
anticipate that our operating results are likely to vary significantly as a
result of a number of factors, including:

         o        the timing of new product introductions by each subsidiary
                  company;

         o        the stage of development of the business of each subsidiary
                  company;

         o        the technical feasibility of each subsidiary company's
                  technologies and techniques;

         o        the novelty of the technology owned by our subsidiary
                  companies;

         o        the accuracy, effectiveness and reliability of products
                  developed by our subsidiary companies;

         o        the level of product acceptance;

         o        the strength of each subsidiary company's intellectual
                  property rights;

         o        the ability of each subsidiary company to avoid infringing the
                  intellectual property rights of others;

         o        each subsidiary company's ability to exploit and commercialize
                  its technology;

         o        the volume and timing of orders received and product line
                  maturation;

         o        the impact of price competition; and

                                       3


         o        each subsidiary company's ability to access distribution
                  channels.

         Many of these factors are beyond our subsidiary companies' control. We
cannot provide any assurance that any subsidiary company will experience growth
in the future or be profitable on an operating basis in any future period.

IF WE, OR OUR SUBSIDIARIES, ENCOUNTER UNFORESEEN DIFFICULTIES AND CANNOT OBTAIN
ADDITIONAL FUNDING ON FAVORABLE TERMS, OUR BUSINESS MAY SUFFER.

         As of December 31, 2003, we had cash and short-term investments of
$50.5 million on our consolidated financial statements.

         To date, our subsidiary companies have relied primarily upon selling
equity securities, including sales to and loans from us, to generate the funds
needed to finance implementing their plans of operations. Our subsidiary
companies may be required to obtain additional financing through bank
borrowings, debt or equity financings or otherwise, which would require us to
make additional investments or face a dilution of our equity interests.

         We cannot assure that we will not encounter unforeseen difficulties
that may deplete our capital resources more rapidly than anticipated. Any
efforts to seek additional funds could be made through equity, debt or other
external financings. Nevertheless, we cannot assure that additional funding will
be available on favorable terms, if at all. If we fail to obtain additional
funding when needed for our subsidiary companies and ourselves, we may not be
able to execute our business plans and our business may suffer.

BECAUSE WE HAVE A LIMITED OPERATING HISTORY, WE CANNOT ASSURE THAT OUR
OPERATIONS WILL BE PROFITABLE.

         We commenced operations in 1993 and, accordingly, have a limited
operating history. In addition, certain of our subsidiary companies are in the
early stages of development and or operations and have limited operating
histories. You should consider our prospects in light of the risks, expenses and
difficulties frequently encountered by companies with such limited operating
histories. Since we have a limited operating history, we cannot assure you that
our operations will be profitable or that we will generate sufficient revenues
to meet our expenditures and support our activities.

         During the fiscal year ended December 31, 2003, we had operating losses
of approximately $25.4 million and net losses of approximately $24.4 million. If
we continue to incur operating losses, we may not have enough money to expand
our business and our subsidiary companies' businesses in the future.

OUR FUTURE SUCCESS DEPENDS IN PART ON THE CONTINUED SERVICE OF OUR KEY
EXECUTIVES, AND THE LOSS OF ANY OF THESE KEY EXECUTIVES COULD ADVERSELY AFFECT
OUR BUSINESS AND OPERATING RESULTS.

         Our success depends in part upon the continued service of our executive
officers, particularly Paul R. Ryan, our Chairman and Chief Executive Officer,
Robert L. Harris, II, our President, and Dr. Amit Kumar, President and Chief
Executive Officer of CombiMatrix Corporation. Neither Messrs. Ryan or Harris nor
Dr. Kumar has an employment or non-competition agreement with us. The loss of
any of these key individuals would be detrimental to our ongoing operations and
prospects.

OUR FUTURE SUCCESS AND THE SUCCESS OF OUR SUBSIDIARY COMPANIES DEPENDS ON OUR
AND THEIR ABILITIES TO ATTRACT AND RETAIN QUALIFIED TECHNICAL PERSONNEL AND
QUALIFIED MANAGEMENT AND MARKETING TEAMS. FAILURE TO DO SO WOULD HARM OUR
ONGOING OPERATIONS AND BUSINESS PROSPECTS.

         We believe that our success will depend on continued employment by us
and our subsidiary companies of senior management and key technical personnel.
Our subsidiary companies will need to attract, retain and motivate qualified
management personnel to execute their current business plans and to successfully
develop commercially viable products and services. Competition for qualified
personnel is intense and we cannot assure you that we will successfully retain
our existing key employees or attract and retain any additional personnel we may
require.

                                       4


         Each of our subsidiary companies has key executives upon whom we
significantly depend, and the success of those subsidiary companies depends on
their ability to retain and motivate those individuals.

FAILURE TO EFFECTIVELY MANAGE OUR GROWTH COULD PLACE STRAINS ON OUR MANAGERIAL,
OPERATIONAL AND FINANCIAL RESOURCES AND COULD ADVERSELY AFFECT OUR BUSINESS AND
OPERATING RESULTS.

         Our growth has placed, and is expected to continue to place, a strain
on our managerial, operational and financial resources. Further, as our
subsidiary companies' businesses grow, we will be required to manage multiple
relationships. Any further growth by us or our subsidiary companies or an
increase in the number of our strategic relationships will increase this strain
on our managerial, operational and financial resources. This strain may inhibit
our ability to achieve the rapid execution necessary to successfully implement
our business plan. In addition, our future success depends on our ability to
expand our organization to match the growth of our subsidiaries.

THE AVAILABILITY OF SHARES FOR SALE IN THE FUTURE COULD REDUCE THE MARKET PRICE
OF OUR COMMON STOCK.

         In the future, we may issue securities to raise cash for acquisitions.
We may also pay for interests in additional subsidiary companies by using a
combination of cash and our common stock or just our common stock. We may also
issue securities convertible into our common stock. Any of these events may
dilute your ownership interest in us and have an adverse impact on the price of
our common stock.

         In addition, sales of a substantial amount of our common stock in the
public market, or the perception that these sales may occur, could reduce the
market price of our common stock. This could also impair our ability to raise
additional capital through the sale of our securities.

DELAWARE LAW AND OUR CHARTER DOCUMENTS CONTAIN PROVISIONS THAT COULD DISCOURAGE
OR PREVENT A POTENTIAL TAKEOVER OF ACACIA RESEARCH CORPORATION THAT MIGHT
OTHERWISE RESULT IN OUR STOCKHOLDERS RECEIVING A PREMIUM OVER THE MARKET PRICE
OF THEIR SHARES.

         Provisions of Delaware law and our certificate of incorporation and
bylaws could make more difficult the acquisition of Acacia Research Corporation
by means of a tender offer, proxy contest or otherwise, and the removal of
incumbent officers and directors. These provisions include:

         o        Section 203 of the Delaware General Corporation Law, which
                  prohibits a merger with a 15%-or-greater stockholder, such as
                  a party that has completed a successful tender offer, until
                  three years after that party became a 15%-or-greater
                  stockholder;

         o        amendment of our bylaws by the stockholders requires a
                  two-thirds approval of the outstanding shares;

         o        the authorization in our certificate of incorporation of
                  undesignated preferred stock, which could be issued without
                  stockholder approval in a manner designed to prevent or
                  discourage a takeover;

         o        provisions in our bylaws eliminating stockholders' rights to
                  call a special meeting of stockholders, which could make it
                  more difficult for stockholders to wage a proxy contest for
                  control of our board of directors or to vote to repeal any of
                  the anti-takeover provisions contained in our certificate of
                  incorporation and bylaws; and

         o        the division of our board of directors into three classes with
                  staggered terms for each class, which could make it more
                  difficult for an outsider to gain control of our board of
                  directors.

         Such potential obstacles to a takeover could adversely affect the
ability of our stockholders to receive a premium price for their stock in the
event another company wants to acquire us.

                                       5


                     RISKS RELATING TO THE COMBIMATRIX GROUP

         The risk factors beginning on this page discuss risks relating to the
CombiMatrix group. Because each holder of AR- CombiMatrix stock is also a holder
of the common stock of one company, Acacia Research Corporation, the risks
associated with the Acacia Technologies group could affect our AR-CombiMatrix
stock. As such, we urge you to read carefully the section "Risks Relating to the
Acacia Technologies Group" below.

THE COMBIMATRIX GROUP HAS A HISTORY OF LOSSES AND EXPECTS TO INCUR ADDITIONAL
LOSSES IN THE FUTURE.

         The CombiMatrix group has sustained substantial losses since its
inception. The CombiMatrix group may never become profitable or if it does, it
may never be able to sustain profitability. We expect the CombiMatrix group to
incur significant research and development, marketing, general and
administrative expenses. As a result, we expect the CombiMatrix group to incur
significant losses for the foreseeable future.

THE COMBIMATRIX GROUP MAY FAIL TO MEET MARKET EXPECTATIONS BECAUSE OF
FLUCTUATIONS IN ITS QUARTERLY OPERATING RESULTS, WHICH COULD CAUSE ITS STOCK
PRICE TO DECLINE.

         The CombiMatrix group's revenues and operating results have fluctuated
in the past and may continue to fluctuate significantly from quarter to quarter
in the future. It is possible that in future periods the CombiMatrix group's
revenues could fall below the expectations of securities analysts or investors,
which could cause the market price of our AR-CombiMatrix stock to decline. The
following are among the factors that could cause the CombiMatrix group's
operating results to fluctuate significantly from period to period:

         o        its unpredictable revenue sources, as described below;

         o        the nature, pricing and timing of the CombiMatrix group's and
                  its competitors' products;

         o        changes in the CombiMatrix group's and its competitors'
                  research and development budgets;

         o        expenses related to, and the CombiMatrix group's ability to
                  comply with, governmental regulations of its products and
                  processes; and

         o        expenses related to, and the results of, patent filings and
                  other proceedings relating to intellectual property rights.

         The CombiMatrix group anticipates significant fixed expenses due in
part to its need to continue to invest in product development. It may be unable
to adjust its expenditures if revenues in a particular period fail to meet its
expectations, which would harm its operating results for that period. As a
result of these fluctuations, the CombiMatrix group believes that
period-to-period comparisons of the CombiMatrix group's financial results will
not necessarily be meaningful, and you should not rely on these comparisons as
an indication of its future performance.

THE COMBIMATRIX GROUP'S REVENUES WILL BE UNPREDICTABLE, AND THIS MAY HARM ITS
FINANCIAL CONDITION.

         The amount and timing of revenues that the CombiMatrix group may
realize from its business will be unpredictable because:

         o        whether products are commercialized and generate revenues
                  depends, in part, on the efforts and timing of its potential
                  customers;

         o        its sales cycles may be lengthy; and

         o        it cannot be sure as to the timing of receipt of payment for
                  its products.

                                       6


         As a result, the CombiMatrix group's revenues may vary significantly
from quarter to quarter, which could make its business difficult to manage and
cause its quarterly results to be below market expectations. If this happens,
the price of the CombiMatrix group's common stock may decline significantly.

TECHNOLOGY COMPANY STOCK PRICES ARE ESPECIALLY VOLATILE, AND THIS VOLATILITY MAY
DEPRESS THE PRICE OF OUR AR-COMBIMATRIX STOCK.

         The stock market has experienced significant price and volume
fluctuations, and the market prices of technology companies, particularly
biotechnology companies, has been highly volatile. We believe that various
factors may cause the market price of our AR-CombiMatrix stock to fluctuate,
perhaps substantially, including, among others, announcements of:

         o        its or its competitors' technological innovations;

         o        developments or disputes concerning patents or proprietary
                  rights;

         o        supply, manufacturing or distribution disruptions or other
                  similar problems;

         o        proposed laws regulating participants in the biotechnology
                  industry;

         o        developments in relationships with collaborative partners or
                  customers;

         o        its failure to meet or exceed securities analysts'
                  expectations of its financial results; or

         o        a change in financial estimates or securities analysts'
                  recommendations.

         In the past, companies that have experienced volatility in the market
price of their stock have been the objects of securities class action
litigation. If our AR-CombiMatrix stock was the object of securities class
action litigation, it could result in substantial costs and a diversion of
management's attention and resources, which could materially harm the business
and financial results of the CombiMatrix group.

THE COMBIMATRIX GROUP IS DEPLOYING NEW AND UNPROVEN TECHNOLOGIES WHICH MAKES
EVALUATION OF ITS BUSINESS AND PROSPECTS DIFFICULT AND IT MAY BE FORCED TO CEASE
OPERATIONS IF IT DOES NOT DEVELOP COMMERCIALLY SUCCESSFUL PRODUCTS.

         The CombiMatrix group has not proven its ability to commercialize
products on a large scale. In order to successfully commercialize products on a
large scale, it will have to make significant investments, including investments
in research and development and testing, to demonstrate their technical benefits
and cost-effectiveness. Problems frequently encountered in connection with the
commercialization of products using new and unproven technologies might limit
its ability to develop and commercialize its products. For example, the
CombiMatrix group's products may be found to be ineffective, unreliable or
otherwise unsatisfactory to potential customers. The CombiMatrix group may
experience unforeseen technical complications in the processes it uses to
develop, manufacture, customize or receive orders for its products. These
complications could materially delay or limit the use of products the
CombiMatrix group attempts to commercialize, substantially increase the
anticipated cost of its products or prevent it from implementing its processes
at appropriate quality and scale levels, thereby causing its business to suffer.

THE COMBIMATRIX GROUP MAY NEED TO RAISE ADDITIONAL CAPITAL IN THE FUTURE, AND IF
ADDITIONAL CAPITAL IS NOT AVAILABLE ON ACCEPTABLE TERMS, THE COMBIMATRIX GROUP
MAY HAVE TO CURTAIL OR CEASE OPERATIONS.

         The CombiMatrix group's future capital requirements will be substantial
and will depend on many factors including how quickly it commercializes its
products, the progress and scope of its collaborative and independent research
and development projects, the filing, prosecution, enforcement and defense of

                                       7


patent claims and the need to obtain regulatory approval for certain products in
the United States or elsewhere. Changes may occur that would cause the
CombiMatrix group's available capital resources to be consumed significantly
sooner than it expects.

         The CombiMatrix group may be unable to raise sufficient additional
capital on favorable terms or at all. If it fails to do so, it may have to
curtail or cease operations or enter into agreements requiring it to relinquish
rights to certain technologies, products or markets because it will not have the
capital necessary to exploit them.

IF THE COMBIMATRIX GROUP DOES NOT ENTER INTO SUCCESSFUL PARTNERSHIPS AND
COLLABORATIONS WITH OTHER COMPANIES, IT MAY NOT BE ABLE TO FULLY DEVELOP ITS
TECHNOLOGIES OR PRODUCTS, AND ITS BUSINESS WOULD BE HARMED.

         Since the CombiMatrix group does not possess all of the resources
necessary to develop and commercialize products that may result from its
technologies on a mass scale, it will need either to grow its sales, marketing
and support group or make appropriate arrangements with strategic partners to
market, sell and support its products. The CombiMatrix group believes that it
will have to enter into additional strategic partnerships to develop and
commercialize future products. If it does not enter into adequate agreements, or
if its existing arrangements or future agreements are not successful, its
ability to develop and commercialize products will be impacted negatively, and
its revenues will be adversely affected.

         The current business of the CombiMatrix group is substantially
dependent on its existing arrangement with Roche. The CombiMatrix group
currently relies upon payments by Roche for a majority of its future revenues
and expends a majority of its resources toward fulfilling its contractual
obligations to Roche. Roche's primary service to the CombiMatrix group is to
distribute and proliferate its technology platform. If the CombiMatrix group
were to lose its relationship with Roche, the CombiMatrix group would be
required to establish a distribution agreement with another partner or
distribute its technology platform itself. This could prove difficult,
time-consuming and expensive, and the CombiMatrix group may not be successful in
achieving this objective.

THE COMBIMATRIX GROUP HAS LIMITED EXPERIENCE COMMERCIALLY MANUFACTURING,
MARKETING OR SELLING ANY OF ITS POTENTIAL PRODUCTS, AND UNLESS IT DEVELOPS THESE
CAPABILITIES, IT MAY NOT BE SUCCESSFUL.

         Even if the CombiMatrix group is able to develop its products for
commercial release on a large-scale, it has limited experience in manufacturing
its products in the volumes that will be necessary for it to achieve commercial
sales and in marketing or selling its products to potential customers. We cannot
assure you that the CombiMatrix group will be able to commercially produce its
products on a timely basis, in sufficient quantities or on commercially
reasonable terms.

THE COMBIMATRIX GROUP FACES INTENSE COMPETITION AND WE CANNOT ASSURE YOU THAT IT
WILL BE SUCCESSFUL.

         The CombiMatrix group expects to compete with companies that design,
manufacture and market instruments for analysis of genetic variation and
function and other applications using established sequential and parallel
testing technologies. The CombiMatrix group is also aware of other biotechnology
companies that have or are developing testing technologies for the SNP
genotyping, gene expression profiling and proteomic markets. The CombiMatrix
group anticipates that it will face increased competition in the future as new
companies enter the market with new technologies and its competitors improve
their current products.

         The markets for the CombiMatrix group's products are characterized by
rapidly changing technology, evolving industry standards, changes in customer
needs, emerging competition and new product introductions. One or more of the
CombiMatrix group's competitors may offer technology superior to those of the
CombiMatrix group and render its technology obsolete or uneconomical. Many of
its competitors have greater financial and personnel resources and more
experience in marketing, sales and research and development than it has. Some of
its competitors currently offer arrays with greater density than it does and
have rights to intellectual property, such as genomic information or proprietary
technology, which provides them with a competitive advantage. If the CombiMatrix
group were not able to compete successfully, its business and financial
condition would be materially harmed.

                                       8


IF THE COMBIMATRIX GROUP'S NEW AND UNPROVEN TECHNOLOGY IS NOT USED BY
RESEARCHERS IN THE PHARMACEUTICAL, BIOTECHNOLOGY AND ACADEMIC COMMUNITIES, ITS
BUSINESS WILL SUFFER.

         The CombiMatrix group's products may not gain market acceptance. In
that event, it is unlikely that its business will succeed. Biotechnology and
pharmaceutical companies and academic research centers have historically
analyzed genetic variation and function using a variety of technologies, and
many of them have made significant capital investments in existing technologies.
Compared to existing technologies, the CombiMatrix group's technologies are new
and unproven. In order to be successful, its products must meet the commercial
requirements of the biotechnology, pharmaceutical and academic communities as
tools for the large-scale analysis of genetic variation and function. Market
acceptance will depend on many factors, including:

         o        the development of a market for its tools for the analysis of
                  genetic variation and function, the study of proteins and
                  other purposes;

         o        the benefits and cost-effectiveness of its products relative
                  to others available in the market;

         o        its ability to manufacture products in sufficient quantities
                  with acceptable quality and reliability and at an acceptable
                  cost;

         o        its ability to develop and market additional products and
                  enhancements to existing products that are responsive to the
                  changing needs of its customers;

         o        the willingness and ability of customers to adopt new
                  technologies requiring capital investments or the reluctance
                  of customers to change technologies in which they have made a
                  significant investment; and

         o        the willingness of customers to transmit test data and permit
                  the CombiMatrix group to transmit test results over the
                  Internet, which will be a necessary component of its product
                  and services packages unless customers purchase or license its
                  equipment for use in their own facilities.

IF THE MARKET FOR ANALYSIS OF GENOMIC INFORMATION DOES NOT DEVELOP OR IF GENOMIC
INFORMATION IS NOT AVAILABLE TO THE COMBIMATRIX GROUP'S POTENTIAL CUSTOMERS, ITS
BUSINESS WILL NOT SUCCEED.

         The CombiMatrix group is designing its technology primarily for
applications in the biotechnology, pharmaceutical and academic communities. The
usefulness of the CombiMatrix group's technology depends in part upon the
availability of genomic data. The CombiMatrix group is initially focusing on
markets for analysis of genetic variation and function, namely SNP genotyping
and gene expression profiling. These markets are new and emerging, and they may
not develop as the CombiMatrix group anticipates, or at all. Also, researchers
may not seek or be able to convert raw genomic data into medically valuable
information through the analysis of genetic variation and function. If genomic
data is not available for use by the CombiMatrix group's customers or if its
target markets do not emerge in a timely manner, or at all, demand for its
products will not develop as it expects, and it may never become profitable.

THE COMBIMATRIX GROUP'S FUTURE SUCCESS DEPENDS ON THE CONTINUED SERVICE OF ITS
ENGINEERING, TECHNICAL AND KEY MANAGEMENT PERSONNEL AND ITS ABILITY TO IDENTIFY,
HIRE AND RETAIN ADDITIONAL ENGINEERING, TECHNICAL AND KEY MANAGEMENT PERSONNEL.

         There is intense competition for qualified personnel in the CombiMatrix
group's industry, particularly for engineers and senior level management. Loss
of the services of, or failure to recruit, engineers or other technical and key
management personnel could be significantly detrimental to the group and could
adversely affect its business and operating results. The CombiMatrix group may
not be able to continue to attract and retain engineers or other qualified
personnel necessary for the development of its products and business or to
replace engineers or other qualified personnel who may leave the group in the
future. The CombiMatrix group's anticipated growth is expected to place
increased demands on its resources and likely will require the addition of new
management personnel.

                                       9


THE EXPANSION OF THE COMBIMATRIX GROUP'S PRODUCT LINES MAY SUBJECT IT TO
REGULATION BY THE UNITED STATES FOOD AND DRUG ADMINISTRATION AND FOREIGN
REGULATORY AUTHORITIES, WHICH COULD PREVENT OR DELAY ITS INTRODUCTION OF NEW
PRODUCTS.

         If the CombiMatrix group manufactures, markets or sells any products
for any regulated clinical or diagnostic applications, those products will be
subject to extensive governmental regulation as medical devices in the United
States by the FDA and in other countries by corresponding foreign regulatory
authorities. The process of obtaining and maintaining required regulatory
clearances and approvals is lengthy, expensive and uncertain. Products that
CombiMatrix Corporation manufactures, markets or sells for research purposes
only are not subject to governmental regulations as medical devices or as
analyte specific reagents to aid in disease diagnosis. We believe that the
CombiMatrix group's success will depend upon commercial sales of improved
versions of products, certain of which cannot be marketed in the United States
and other regulated markets unless and until the CombiMatrix group obtains
clearance or approval from the FDA and its foreign counterparts, as the case may
be. Delays or failures in receiving these approvals may limit our ability to
benefit from new CombiMatrix group products.

AS THE COMBIMATRIX GROUP'S OPERATIONS EXPAND, ITS COSTS TO COMPLY WITH
ENVIRONMENTAL LAWS AND REGULATIONS WILL INCREASE, AND FAILURE TO COMPLY WITH
THESE LAWS AND REGULATIONS COULD HARM ITS FINANCIAL RESULTS.

         The CombiMatrix group's operations involve the use, transportation,
storage and disposal of hazardous substances, and as a result it is subject to
environmental and health and safety laws and regulations. As the CombiMatrix
group expands its operations, its use of hazardous substances will increase and
lead to additional and more stringent requirements. The cost to comply with
these and any future environmental and health and safety regulations could be
substantial. In addition, the CombiMatrix group's failure to comply with laws
and regulations, and any releases of hazardous substances into the environment
or at its disposal sites, could expose the CombiMatrix group to substantial
liability in the form of fines, penalties, remediation costs and other damages,
or could lead to a curtailment or shut down of its operations. These types of
events, if they occur, would adversely impact the group's financial results.

THE COMBIMATRIX GROUP'S BUSINESS DEPENDS ON ISSUED AND PENDING PATENTS, AND THE
LOSS OF ANY PATENTS OR THE GROUP'S FAILURE TO SECURE THE ISSUANCE OF PATENTS
COVERING ELEMENTS OF ITS BUSINESS PROCESSES WOULD MATERIALLY HARM ITS BUSINESS
AND FINANCIAL CONDITION.

         The CombiMatrix group's success depends on its ability to protect and
exploit its intellectual property. The CombiMatrix group currently has two
patents issued in the United States, one patent issued in Europe and more than
44 patent applications pending in the United States, Europe and elsewhere. The
patent application process before the United States Patent and Trademark Office
and other similar agencies in other countries is initially confidential in
nature. Patents that are filed outside the United States, however, are published
approximately eighteen months after filing. The CombiMatrix group cannot
determine in a timely manner whether patent applications covering technology
that competes with its technology have been filed in the United States or other
foreign countries or which, if any, will ultimately issue or be granted as
enforceable patents. Some of the CombiMatrix group's patent applications may
claim compositions, methods or uses that may also be claimed in patent
applications filed by others. In some or all of these applications, a
determination of priority of inventorship may need to be decided in a proceeding
before the United States Patent and Trademark Office or a foreign regulatory
body or a court. If the CombiMatrix group is unsuccessful in these proceedings,
it could be blocked from further developing, commercializing or selling
products. Regardless of the ultimate outcome, this process is time-consuming and
expensive.

ANY INABILITY TO ADEQUATELY PROTECT THE COMBIMATRIX GROUP'S PROPRIETARY
TECHNOLOGIES COULD MATERIALLY HARM THE COMBIMATRIX GROUP'S COMPETITIVE POSITION
AND FINANCIAL RESULTS.

         If the CombiMatrix group does not protect its intellectual property
adequately, competitors may be able to use its technologies and erode any
competitive advantage that it may have. The laws of some foreign countries do
not protect proprietary rights to the same extent as the laws of the United
States, and many companies have encountered significant problems in protecting
their proprietary rights abroad. These problems can be caused by the absence of
rules and methods for defending intellectual property rights.

                                       10


         The patent positions of companies developing tools for the
biotechnology, pharmaceutical and academic communities, including the
CombiMatrix group's patent position, generally are uncertain and involve complex
legal and factual questions. The CombiMatrix group will be able to protect its
proprietary rights from unauthorized use by third parties only to the extent
that its proprietary technologies are covered by valid and enforceable patents
or are effectively maintained as trade secrets. The CombiMatrix group's existing
patents and any future issued or granted patents it obtains may not be
sufficiently broad in scope to prevent others from practicing its technologies
or from developing competing products. There also is a risk that others may
independently develop similar or alternative technologies or designs around the
CombiMatrix group's patented technologies. In addition, others may oppose or
invalidate its patents, or its patents may fail to provide it with any
competitive advantage. Enforcing the CombiMatrix group's intellectual property
rights may be difficult, costly and time-consuming and ultimately may not be
successful.

         The CombiMatrix group also relies upon trade secret protection for its
confidential and proprietary information. While it has taken security measures
to protect its proprietary information, these measures may not provide adequate
protection for its trade secrets or other proprietary information. The
CombiMatrix group seeks to protect its proprietary information by entering into
confidentiality and invention disclosure and transfer agreements with employees,
collaborators and consultants. Nevertheless, employees, collaborators or
consultants may still disclose its proprietary information, and the CombiMatrix
group may not be able to meaningfully protect its trade secrets. In addition,
others may independently develop substantially equivalent proprietary
information or techniques or otherwise gain access to its trade secrets.

ANY LITIGATION TO PROTECT THE COMBIMATRIX GROUP'S INTELLECTUAL PROPERTY OR ANY
THIRD-PARTY CLAIMS OF INFRINGEMENT, COULD DIVERT SUBSTANTIAL TIME AND MONEY FROM
THE COMBIMATRIX GROUP'S BUSINESS AND COULD SHUT DOWN SOME OF ITS OPERATIONS.

         The CombiMatrix group's commercial success depends in part on its
non-infringement of the patents or proprietary rights of third parties. Many
companies developing tools for the biotechnology and pharmaceutical industries
use litigation aggressively as a strategy to protect and expand the scope of
their intellectual property rights. Accordingly, third parties may assert that
the CombiMatrix group is employing their proprietary technology without
authorization. In addition, third parties may claim that use of the CombiMatrix
group's technologies infringes their current or future patents. The CombiMatrix
group could incur substantial costs and the attention of its management and
technical personnel could be diverted while defending ourselves against any of
these claims. The CombiMatrix group may incur the same liabilities in enforcing
its patents against others. The CombiMatrix group has not made any provision in
its financial plans for potential intellectual property related litigation, and
it may not be able to pursue litigation as aggressively as competitors with
substantially greater financial resources.

         If parties making infringement claims against the CombiMatrix group are
successful, they may be able to obtain injunctive or other equitable relief,
which effectively could block the CombiMatrix group's ability to further
develop, commercialize and sell products, and could result in the award of
substantial damages against it. If the CombiMatrix group is unsuccessful in
protecting and expanding the scope of its intellectual property rights, its
competitors may be able to develop, commercialize and sell products that compete
with it using similar technologies or obtain patents that could effectively
block its ability to further develop, commercialize and sell its products. In
the event of a successful claim of infringement against the CombiMatrix group,
we may be required to pay substantial damages and either discontinue those
aspects of its business involving the technology upon which it infringed or
obtain one or more licenses from third parties. While the CombiMatrix group may
license additional technology in the future, it may not be able to obtain these
licenses at a reasonable cost, or at all. In that event, it could encounter
delays in product introductions while it attempts to develop alternative methods
or products, which may not be successful. Defense of any lawsuit or failure to
obtain any of these licenses could prevent it from commercializing available
products.

                                       11


                 RISKS RELATING TO THE ACACIA TECHNOLOGIES GROUP

         The risk factors beginning on this page discuss risks relating to the
Acacia Technologies group. Because each holder of AR-Acacia Technologies stock
is a holder of the common stock of one company, Acacia Research Corporation, the
risks associated with the CombiMatrix group could affect the AR-Acacia
Technologies stock. As such, we also urge you to read carefully the section
"Risks Relating to the CombiMatrix Group" above.

THE ACACIA TECHNOLOGIES GROUP HAS INCURRED LOSSES IN THE PAST AND EXPECTS TO
INCUR ADDITIONAL LOSSES IN THE FUTURE.

         The Acacia Technologies group has sustained substantial losses in the
past. We expect the Acacia Technologies group to incur significant research and
development, marketing, general and administrative expenses. As a result, we
expect the Acacia Technologies group to incur significant losses for the
foreseeable future.

THE V-CHIP TECHNOLOGY PATENT HELD BY THE ACACIA TECHNOLOGIES GROUP EXPIRED IN
JULY 2003, AND IF THE GROUP DOES NOT DEVELOP OTHER RECURRING SOURCES OF REVENUE,
ITS FINANCIAL CONDITION WILL BE ADVERSELY IMPACTED.

         The Acacia Technologies group, and Acacia Research Corporation as a
whole, has generated substantially all of its revenues from licensing the V-chip
technology to television manufacturers. The Acacia Technologies group's patent
on the V-chip technology expired in July 2003. The Acacia Technologies group
will not be able to collect royalties for televisions containing V-chip
technology sold after the expiration of that patent, but it may still collect
revenues from the sale of such televisions in the U.S. before that date. The
Acacia Technologies group is beginning to market its digital media transmission
technology and is developing other technologies and products. The eventual
licensing and sale of these technologies is intended to replace the revenue
currently being generated by licensing its V-chip technology. If the Acacia
Technologies group does not succeed in developing such technologies or is unable
to commercially license its existing and future technologies, its financial
condition will be adversely impacted.

THE ACACIA TECHNOLOGIES GROUP MAY FAIL TO MEET MARKET EXPECTATIONS BECAUSE OF
FLUCTUATIONS IN ITS QUARTERLY OPERATING RESULTS, WHICH COULD CAUSE THE PRICE OF
AR-ACACIA TECHNOLOGIES STOCK TO DECLINE.

         The Acacia Technologies group's revenues and operating results have
fluctuated in the past and may continue to fluctuate significantly from quarter
to quarter in the future. It is possible that in future periods the Acacia
Technologies group's revenues could fall below the expectations of securities
analysts or investors, which could cause the market price of our AR-Acacia
Technologies stock to decline. The following are among the factors that could
cause the Acacia Technologies group's operating results to fluctuate
significantly from period to period:

         o        its unpredictable revenue sources, as described below;

         o        costs related to acquisitions, alliances, licenses and other
                  efforts to expand its operations;

         o        the timing of payments under the terms of any customer or
                  license agreements into which the Acacia Technologies group
                  may enter; and

         o        expenses related to, and the results of, patent filings and
                  other proceedings relating to intellectual property rights.

THE ACACIA TECHNOLOGIES GROUP'S REVENUES WILL BE UNPREDICTABLE, AND THIS MAY
HARM ITS FINANCIAL CONDITION.

         The amount and timing of revenues that the Acacia Technologies group
may realize from its business will be unpredictable because:

         o        whether the Acacia Technologies group generates revenues
                  depends, in part, on the success of its licensing efforts;

                                       12


         o        its cycle of obtaining licensees may be lengthy; and

         o        it cannot be sure as to the timing of receipt of payment.

         As a result, the Acacia Technologies group's revenues may vary
significantly from quarter to quarter, which could make its business difficult
to manage and cause its quarterly results to be below market expectations. If
this happens, the price of our AR-Acacia Technologies stock may decline
significantly.

TECHNOLOGY COMPANY STOCK PRICES ARE ESPECIALLY VOLATILE, AND THIS VOLATILITY MAY
DEPRESS THE PRICE OF OUR AR-ACACIA TECHNOLOGIES STOCK.

         The stock market has experienced significant price and volume
fluctuations, and the market prices of technology companies have been highly
volatile. We believe that various factors may cause the market price of our
AR-Acacia Technologies stock to fluctuate, perhaps substantially, including,
among others, announcements of:

         o        its or its competitors' technological innovations;

         o        developments or disputes concerning patents or proprietary
                  rights;

         o        developments in relationships with licensees;

         o        its failure to meet or exceed securities analysts'
                  expectations of its financial results; or

         o        a change in financial estimates or securities analysts'
                  recommendations.

         In the past, companies that have experienced volatility in the market
price of their stock have been the objects of securities class action
litigation. If our AR-Acacia Technologies stock was the object of securities
class action litigation, it could result in substantial costs and a diversion of
management's attention and resources, which could materially harm the business
and financial results of the Acacia Technologies group.

THE ACACIA TECHNOLOGIES GROUP FACES INTENSE COMPETITION, AND WE CANNOT ASSURE
YOU THAT IT WILL BE SUCCESSFUL.

         Although the Acacia Technologies group believes that Acacia Media
Technologies has marketing and licensing rights to enforceable patents and other
intellectual property relating to video and audio on demand, the Acacia
Technologies group cannot assure you that other companies will not develop
competing technologies that offer better or less expensive alternatives to those
offered by Acacia Media Technologies. In the event a competing technology
emerges, Acacia Media Technologies would expect substantial additional
competition.

THE MARKETS SERVED BY THE ACACIA TECHNOLOGIES GROUP ARE SUBJECT TO RAPID
TECHNOLOGICAL CHANGE, AND IF THE ACACIA TECHNOLOGIES GROUP IS UNABLE TO DEVELOP
AND INTRODUCE NEW PRODUCTS, ITS REVENUES COULD STOP GROWING OR COULD DECLINE.

         The markets served by the Acacia Technologies group frequently undergo
transitions in which products rapidly incorporate new features and performance
standards on an industry-wide basis. Products for communications applications,
as well as for high-speed computing applications, are based on continually
evolving industry standards. A significant portion of the Acacia Technologies
group's revenues in recent periods has been, and is expected to continue to be,
derived from licensing of technologies based on existing transmission standards.
The Acacia Technologies group's ability to compete in the future will, however,
depend on its ability to identify and ensure compliance with evolving industry
standards.

                                       13


THE ACACIA TECHNOLOGIES GROUP'S SUCCESS IS BASED ON ITS ABILITY TO PROTECT ITS
PROPRIETARY TECHNOLOGY AND ITS ABILITY TO DEFEND ITSELF AGAINST INFRINGEMENT
CLAIMS.

         The success of the Acacia Technologies group relies, to varying
degrees, on its proprietary rights and their protection or exclusivity. Although
reasonable efforts will be taken to protect the Acacia Technologies group's
proprietary rights, the complexity of international trade secret, copyright,
trademark and patent law, and common law, coupled with limited resources and the
demands of quick delivery of products and services to market, create risk that
these efforts will prove inadequate. For example, in our pending litigation
against certain television manufacturers alleging their infringement of
Soundview Technologies' V-chip patent, a motion for summary judgment filed by
the defendants was granted in September 2002. The court ruled that the
defendants did not infringe on Soundview Technologies' patent. If we are
unsuccessful in our intended appeal of this ruling, legal principles will
preclude us from claiming infringement of our patents by other parties.
Accordingly, if we are unsuccessful in this or other litigation to protect our
intellectual property rights, the future revenues of the Acacia Technologies
group could be adversely affected.

         From time to time, the Acacia Technologies group may be subject to
third-party claims in the ordinary course of business, including claims of
alleged infringement of proprietary rights. Any such claims may harm the Acacia
Technologies group by subjecting it to significant liability for damage and
invalidating its proprietary rights. These types of claims, with or without
merit, could subject the Acacia Technologies group to costly litigation and
diversion of its technical and management personnel. The Acacia Technologies
group depends largely on the protection of enforceable patent rights. The Acacia
Technologies group has applications on file with the U.S. Patent and Trademark
Office seeking patents on its core technologies and has patents or rights to
patents that have been issued. We cannot assure you that the pending patent
applications of the Acacia Technologies group will be issued, that third parties
will not violate, or attempt to invalidate these intellectual property rights,
or that certain aspects of those intellectual property will not be
reverse-engineered by third parties without violating the patent rights of the
Acacia Technologies group.

          For Acacia Media Technologies and Soundview Technologies, proprietary
rights constitute their only significant assets. The Acacia Technologies group
also owns licenses from third parties and it is possible that it could become
subject to infringement actions based upon such licenses. The Acacia
Technologies group generally obtains representations as to the origin and
ownership of such licensed content. However, this may not adequately protect the
Acacia Technologies group. The Acacia Technologies group enters into
confidentiality agreements with third parties and generally limits access to
information relating to its proprietary rights. Despite these precautions, third
parties may be able to gain access to and use the Acacia Technologies group's
proprietary rights to develop competing technologies and products with similar
or better features and prices. Any substantial unauthorized use of the Acacia
Technologies group's proprietary rights could materially and adversely affect
its business and operational results.

                     RISKS RELATING TO OUR CAPITAL STRUCTURE

HOLDERS OF BOTH CLASSES OF OUR STOCK ARE STOCKHOLDERS OF ONE COMPANY, AND THE
FINANCIAL PERFORMANCE OF ONE GROUP COULD AFFECT THE OTHER, THUS EXPOSING THE
HOLDERS OF EACH GROUP'S STOCK TO THE RISKS OF AN INVESTMENT IN THE ENTIRE
COMPANY.

         Holders of AR-CombiMatrix stock and AR-Acacia Technologies stock are
stockholders of a single company. The CombiMatrix group and the Acacia
Technologies group are not separate legal entities. As a result, stockholders
will continue to be subject to all of the risks of an investment in Acacia
Research Corporation and all of our businesses, assets and liabilities. The
issuance of our AR-CombiMatrix stock and our AR-Acacia Technologies stock and
the allocation of assets and liabilities and stockholders' equity between the
CombiMatrix group and the Acacia Technologies group did not result in a
distribution or spin-off to stockholders of any of our assets or liabilities and
did not affect ownership of our assets or responsibility for our liabilities or
those of our subsidiaries. The assets we attribute to one group could be subject
to the liabilities of the other group, whether such liabilities arise from
lawsuits, contracts or indebtedness that we attribute to the other group. If we
are unable to satisfy one group's liabilities out of the assets we attribute to
it, we may be required to satisfy those liabilities with assets we have
attributed to the other group.

                                       14


         Financial effects from one group that affect our consolidated results
of operations or financial condition could, if significant, affect the results
of operations or financial condition of the other group and the market price of
the common stock relating to the other group. In addition, net losses of either
group and dividends or distributions on, or repurchases of, either class of
common stock will reduce the funds we can pay as dividends on each class of
common stock under Delaware law. For these reasons, you should read our
consolidated financial information with the financial information we provide for
each group.

THE MARKET PRICE OF EITHER CLASS OF OUR COMMON STOCK MAY NOT REFLECT THE
SEPARATE PERFORMANCE OF THE GROUP RELATED TO THAT CLASS OF COMMON STOCK.

         The market price of our AR-CombiMatrix stock or AR-Acacia Technologies
stock may not reflect the separate performance of the business of the group
relating to that class of common stock. The market price of either class of
common stock could simply reflect the performance of Acacia Research Corporation
as a whole, or the market price of either class of common stock could move
independently of the performance of the business of either group. Investors may
discount the value of either class of common stock because it is part of a
common enterprise rather than a stand-alone company.

THE MARKET PRICE OF EITHER CLASS OF OUR COMMON STOCK MAY BE AFFECTED BY FACTORS
THAT DO NOT AFFECT TRADITIONAL COMMON STOCK.

         THE COMPLEX NATURE OF THE TERMS OF OUR AR-COMBIMATRIX STOCK AND
         AR-ACACIA TECHNOLOGIES STOCK MAY ADVERSELY AFFECT THE MARKET PRICE OF
         EITHER CLASS OF COMMON STOCK.

         The complex nature of the terms of our two classes of common stock,
such as the convertibility of AR-CombiMatrix stock into AR-Acacia Technologies
stock, or vice versa, and the potential difficulties investors may have
understanding these terms, may adversely affect the market price of either class
of common stock.

         THE MARKET PRICE OF OUR AR-COMBIMATRIX STOCK OR AR-ACACIA TECHNOLOGIES
         STOCK MAY BE ADVERSELY AFFECTED BY THE FACT THAT HOLDERS HAVE LIMITED
         LEGAL INTERESTS IN THE GROUP RELATING TO THE CLASS OF COMMON STOCK HELD
         AS A SEPARATE LEGAL ENTITY.

         For example, as described in greater detail in the subsequent risk
factors, holders of either class of common stock generally do not have separate
class voting rights with respect to significant matters affecting either group.
In addition, upon our liquidation or dissolution, holders of either class of
common stock will not have specific rights to the assets of the group relating
to the class of common stock held and will not be entitled to receive proceeds
that are proportional to the relative performance of that group.

         THE MARKET PRICE OF OUR AR-COMBIMATRIX STOCK OR AR-ACACIA TECHNOLOGIES
         STOCK MAY BE ADVERSELY AFFECTED BY EVENTS INVOLVING THE GROUP RELATING
         TO THE OTHER CLASS OF COMMON STOCK OR THE PERFORMANCE OF THE CLASS OF
         COMMON STOCK RELATING TO THAT GROUP.

         Events, such as earnings announcements or other developments concerning
one group that the market does not view favorably and which thus adversely
affect the market price of the class of common stock relating to that group, may
adversely affect the market price of the class of common stock relating to the
other group. Because both classes of common stock are common stock of Acacia
Research Corporation, an adverse market reaction to one class of common stock
may, by association, cause an adverse reaction to the other class of common
stock. This reaction may occur even if the triggering event was not material to
us as a whole.

THE HOLDERS OF AR-COMBIMATRIX STOCK AND THE HOLDERS OF AR-ACACIA TECHNOLOGIES
STOCK HAVE ONLY LIMITED SEPARATE STOCKHOLDER RIGHTS.

         Holders of AR-CombiMatrix stock and AR-Acacia Technologies stock have
the rights customarily held by common stockholders. They also have these
specific rights related to their corresponding group:

                                       15


         o        certain rights with regard to dividends and liquidation;

         o        requirements for a mandatory dividend, redemption or
                  conversion upon the disposition of all or substantially all of
                  the assets of their corresponding group; and

         o        a right to vote on matters as a separate voting class in the
                  limited circumstances provided under Delaware law, by stock
                  exchange rules or as determined by our board of directors
                  (such as an amendment of our certificate of incorporation that
                  changes the rights, privileges or preferences of the class of
                  stock held by such stockholders).

         We will not hold separate stockholder meetings for holders of
AR-CombiMatrix stock and AR-Acacia Technologies stock.

THE HOLDERS OF AR-COMBIMATRIX STOCK AND THE HOLDERS OF AR-ACACIA TECHNOLOGIES
STOCK WILL HAVE CERTAIN LIMITS ON THEIR RESPECTIVE VOTING POWERS.

         GROUP COMMON STOCK WITH A MAJORITY OF VOTING POWER CAN CONTROL VOTING
         OUTCOMES.

         The holders of AR-CombiMatrix stock and AR-Acacia Technologies stock
will vote together as a single class, except in limited circumstances. If a
separate vote on a matter by the holders of either our AR-CombiMatrix stock or
our AR-Acacia Technologies stock is not required under Delaware law or by stock
exchange rules, and if our board of directors does not require a separate vote,
either class of common stock that is entitled to more than the number of votes
required to approve such matter could control the outcome of such vote - even if
the matter involves a divergence or conflict of the interests between the
holders of our AR-CombiMatrix stock and our AR-Acacia Technologies stock. In
addition, if the holders of common stock having a majority of the voting power
of all shares of common stock outstanding approve a merger, the terms of which
did not require separate class voting under stock exchange rules, then the
merger could be consummated - even if the holders of a majority of either class
of common stock were to vote against the merger.

         GROUP COMMON STOCK WITH LESS THAN MAJORITY VOTING POWER CAN BLOCK
         ACTION IF A CLASS VOTE IS REQUIRED.

         If Delaware law, stock exchange rules or our board of directors
requires a separate vote on a matter by the holders of either our AR-CombiMatrix
stock or our AR-Acacia Technologies stock, such as a proposal to amend the terms
of one class of stock, those holders could prevent approval of the matter, even
if the holders of a majority of the total number of votes cast or entitled to be
cast, voting together as a class, were to vote in favor of it.

         HOLDERS OF ONLY ONE CLASS OF COMMON STOCK CANNOT ENSURE THAT THEIR
         VOTING POWER WILL BE SUFFICIENT TO PROTECT THEIR INTERESTS.

         Since the relative voting power per share of AR-CombiMatrix stock and
AR-Acacia Technologies stock will fluctuate based on the market values of the
two classes of common stock, the relative voting power of a class of common
stock could decrease. As a result, holders of shares of only one of the two
classes of common stock cannot ensure that their voting power will be sufficient
to protect their interests.

OUR RESTATED CERTIFICATE OF INCORPORATION MAY BE AMENDED TO INCREASE OR DECREASE
THE AUTHORIZED SHARES OF EITHER CLASS OF COMMON STOCK WITHOUT THE APPROVAL OF
EACH CLASS VOTING SEPARATELY.

         Our restated certificate of incorporation provides that an amendment to
our restated certificate to increase or decrease the number of authorized shares
of either class of common stock will require the approval of the holders of a
majority of the voting power of all shares of common stock, voting together as a
single class, and will not require the approval of each class of stock voting as
a separate class. Accordingly, if the holders of one class of common stock hold
a majority of the voting power of all shares of common stock, then that majority
could approve an amendment to our restated certificate to increase or decrease
the authorized shares of stock of either class without the approval of the
holders of the minority class of stock.

                                       16


STOCKHOLDERS MAY NOT HAVE ANY REMEDIES FOR BREACH OF FIDUCIARY DUTIES IF ANY
ACTION BY OUR DIRECTORS OR OFFICERS HAS A DISADVANTAGEOUS EFFECT ON EITHER CLASS
OF COMMON STOCK.

         Stockholders may not have any remedies if any action or decision of our
directors and officers has a disadvantageous effect on either class of common
stock compared to the other class of common stock. We are not aware of any legal
precedent under Delaware law involving the fiduciary duties of directors and
officers of corporations having two classes of common stock, or separate classes
or series of capital stock, the rights of which, like our AR-CombiMatrix stock
and AR-Acacia Technologies stock, are defined by reference to separate
businesses of the corporation.

         Principles of Delaware law established in cases involving differing
treatment of two classes of capital stock or two groups of holders of the same
class of capital stock provide that a board of directors owes an equal duty to
all stockholders regardless of class or series. Under these principles of
Delaware law and the related principle known as the "business judgment rule,"
absent abuse of discretion, a good faith business decision made by a
disinterested and adequately informed board of directors, board of directors'
committee or officer with respect to any matter having different effects on
holders of AR-CombiMatrix stock and holders of AR-Acacia Technologies stock
would be a defense to any challenge to such determination made by or on behalf
of the holders of either class of common stock.

NUMEROUS POTENTIAL CONFLICTS OF INTERESTS EXIST BETWEEN OUR AR-COMBIMATRIX STOCK
AND OUR AR-ACACIA TECHNOLOGIES STOCK WHICH MAY BE DIFFICULT TO RESOLVE BY OUR
BOARD OR WHICH MAY BE RESOLVED ADVERSELY TO ONE OF THE CLASSES.

         The existence of separate classes of common stock could give rise to
occasions when the interests of the holders of AR-CombiMatrix stock and
AR-Acacia Technologies stock diverge or conflict. Examples include
determinations by our directors or officers to:

         o        pay or omit the payment of dividends on AR-CombiMatrix stock
                  or AR-Acacia Technologies stock;

         o        allocate consideration to be received by holders of each of
                  the classes of common stock in connection with a merger or
                  consolidation involving Acacia Research Corporation;

         o        convert one class of common stock into shares of the other;

         o        approve certain dispositions of the assets of either group;

         o        allocate the proceeds of future issuances of our stock either
                  to the Acacia Technologies group or the CombiMatrix group;

         o        allocate corporate opportunities between the groups; and

         o        make other operational and financial decisions with respect to
                  one group that could be considered detrimental to the other
                  group.

         When making decisions with regard to matters that create potential
diverging or conflicting interests, our directors and officers will act in
accordance with their fiduciary duties, the terms of our restated certificate of
incorporation, and, to the extent applicable, our management and allocation
policies.

         THE PERFORMANCE OF ONE GROUP OR THE DIVIDENDS PAID TO ONE GROUP MAY
         ADVERSELY AFFECT THE DIVIDENDS AVAILABLE FOR THE OTHER GROUP.

         Our board of directors currently has no intention to pay dividends on
our AR-CombiMatrix stock or our AR-Acacia Technologies stock. Determinations as
to future dividends on our AR-CombiMatrix stock and our AR-Acacia Technologies
stock will be based primarily on the financial condition, results of operations

                                       17


and business requirements of the relevant group and Acacia Research Corporation
as a whole. Subject to the limitations referred to below, our board of directors
has the authority to declare and pay dividends on our AR-CombiMatrix stock and
our AR-Acacia Technologies stock in any amount and could, in its sole
discretion, declare and pay dividends exclusively on our AR-CombiMatrix stock,
exclusively on our AR-Acacia Technologies stock, or on both, in equal or unequal
amounts. Our board of directors will not be required to consider the amount of
dividends previously declared on each class, the respective voting or
liquidation rights of each class or any other factor.

         The performance of one group may cause our board of directors to pay
more or less dividends on the common stock relating to the other group than if
that other group was a stand-alone company. In addition, Delaware law and our
restated certificate of incorporation impose limitations on the amount of
dividends which may be paid on each class of common stock.

         PROCEEDS OF MERGERS OR CONSOLIDATIONS MAY BE ALLOCATED UNFAVORABLY.

         Our restated certificate of incorporation does not contain any
provisions governing how consideration to be received by holders of common stock
in connection with a merger or consolidation involving Acacia Research
Corporation is to be allocated among holders of each class of common stock. Our
board of directors will determine the percentage of the consideration to be
allocated to holders of each class of common stock in any such transaction. Such
percentage may be materially more or less than that which might have been
allocated to such holders had our board of directors chosen a different method
of allocation.

         HOLDERS OF EITHER CLASS OF COMMON STOCK MAY BE ADVERSELY AFFECTED BY A
         CONVERSION OF GROUP COMMON STOCK.

         Our board of directors could, in its sole discretion and without
stockholder approval, determine to convert shares of AR-Acacia Technologies
stock into shares of AR-CombiMatrix stock, or vice versa, at a time when either
or both classes of common stock may be considered to be overvalued or
undervalued. Any such conversion would dilute the interests in Acacia Research
Corporation of the holders of the class of common stock being issued in the
conversion. It could also give holders of shares of the class of common stock
converted a greater or lesser premium than any premium that might be paid by a
third-party buyer of all or substantially all of the assets of the group whose
stock is converted.

         HOLDERS OF EITHER CLASS OF COMMON STOCK COULD BE ADVERSELY AFFECTED BY
         A DISPOSITION OF THE ASSETS ATTRIBUTED TO THEIR RESPECTIVE GROUPS.

         Our board of directors could, in its sole discretion and without
stockholder approval, determine to dispose of all or substantially all the
assets of a group. If a disposition of group assets occurs at a time when those
assets are considered undervalued, then holders of that group's stock would
receive less consideration than they could have received had the assets been
disposed of at a time when they had a higher value.

         PROCEEDS OF FUTURE ISSUANCES OF OUR STOCK COULD BE ATTRIBUTED
         UNFAVORABLY.

         We may in the future issue a new class of stock, such as a class of
preferred stock, or additional shares of AR-CombiMatrix stock or AR-Acacia
Technologies stock. Proceeds from any future issuance of any class of stock
would be attributed among the CombiMatrix group or the Acacia Technologies group
as determined by our board of directors. There is no requirement that the
proceeds from an issuance of AR-CombiMatrix stock or AR-Acacia Technologies
stock be attributed to the corresponding group. Such allocations might be
materially more or less for the respective groups than what might have been
attributed had our board of directors chosen a different allocation method.
Also, any designated preferred class may be designed to reflect the performance
of Acacia Research Corporation as a whole, rather than the performance of the
CombiMatrix group or the Acacia Technologies group.

                                       18


         ALLOCATION OF CORPORATE OPPORTUNITIES COULD FAVOR ONE GROUP OVER
         ANOTHER.

         Our board of directors may be required to allocate corporate
opportunities between the groups. In some cases, our directors could determine
that a corporate opportunity, such as a business that we are acquiring, should
be shared by the groups. Any such decisions could favor one group at the expense
of the other.

         OTHER OPERATIONAL AND FINANCIAL DECISIONS WHICH MAY FAVOR ONE GROUP
         OVER THE OTHER.

         Our board of directors or our senior officers will review other
operational and financial matters affecting the CombiMatrix group and the Acacia
Technologies group, including the allocation of financing resources and capital,
technology and know-how and corporate overhead, taxes, debt, interest and other
matters. Any decision of our board of directors or our senior officers in these
matters could favor one group at the expense of the other.

OUR BOARD OF DIRECTORS MAY CHANGE OUR MANAGEMENT AND ALLOCATION POLICIES WITHOUT
STOCKHOLDER APPROVAL TO THE DETRIMENT OF EITHER GROUP.

         Our board of directors may modify or rescind our policies with respect
to the allocation of corporate overhead, taxes, debt, interest and other
matters, or may adopt additional policies, in its sole discretion without
stockholder approval. A decision to modify or rescind these policies, or adopt
additional policies could have different effects on holders of either class of
common stock or could result in a benefit or detriment to one class of
stockholders compared to the other class. Our board of directors will make any
such decision in accordance with its good faith business judgment that the
decision is in the best interests of Acacia Research Corporation and all of our
stockholders as a whole.

EITHER GROUP MAY FINANCE THE OTHER GROUP ON TERMS UNFAVORABLE TO ONE OF THE
GROUPS.

         We may transfer cash and other property between groups to finance their
business activities. The group providing the financing will be subject to the
risks relating to the group receiving the financing. We will account for those
transfers generally as a short-term or long-term loan between groups or as a
repayment of a previous borrowing.

THERE ARE LIMITS ON THE CONSIDERATION WHICH MAY BE RECEIVED BY THE STOCKHOLDERS
IN THE EVENT OF THE DISPOSITION OF ASSETS OF A GROUP.

         Our restated certificate of incorporation provides that if a
disposition of all or substantially all of the properties and assets of either
group occurs, we must, subject to certain exceptions:

         o        distribute through a dividend or redemption to holders of the
                  class of common stock relating to such group an amount equal
                  to the net proceeds of such disposition; or

         o        convert at a 10% premium such common stock into shares of the
                  class of common stock relating to the other group.

         If the group subject to the disposition were a separate, independent
company and its shares were acquired by another person, certain costs of that
disposition, including corporate level taxes, might not be payable in connection
with that acquisition. As a result, stockholders of the separate, independent
company might receive a greater amount than the net proceeds that would be
received by holders of the class of common stock relating to that group if the
assets of such group were sold. In addition, we cannot assure you that the net
proceeds per share of the common stock relating to that group will be equal to
or more than the market value per share of such common stock prior to or after
announcement of a disposition.

         The term "substantially all of the properties and assets" of a group is
subject to potentially conflicting interpretations. Resolution of such a dispute
could adversely impact the holders of either the class of common stock related
to the assets being disposed or the holders of the other class because the

                                       19


consideration, if any, to be received by the holders of the class related to the
disposed assets may depend on whether the disposition involved "substantially
all" of the properties and assets of that class.

HOLDERS OF EITHER CLASS OF COMMON STOCK MAY BE ADVERSELY AFFECTED BY A
REDEMPTION OF THEIR COMMON STOCK.

         We are entitled to redeem the outstanding common stock relating to a
group when all or substantially all of that group's assets are sold. We can
redeem the assets for cash, securities, a combination of cash and securities or
other property at fair value. A disposition-related redemption could occur when
the assets being disposed of are considered undervalued. If that were the case,
the holders of our common stock related to that group would receive less
consideration for their shares than they may deem reasonable.

         We can also redeem on a pro rata basis all of the outstanding shares of
a group's common stock for shares of the common stock of one or more of our
wholly owned subsidiaries. If this were to occur, the holders of the redeemed
class of common stock would no longer have stockholder voting rights in Acacia
Research Corporation or any other benefits to be derived from holding a class of
stock in Acacia Research Corporation. In addition, if the outstanding shares of
a class of our common stock are redeemed for shares that are not publicly
traded, the holders of such redeemed stock will no longer be able to publicly
trade their shares and accordingly their investment will be substantially less
liquid.

OUR CAPITAL STRUCTURE AND THE VARIABLE VOTE PER SHARE COULD ENABLE A POTENTIAL
ACQUIRER TO TAKE CONTROL OF OUR COMPANY THROUGH THE ACQUISITION OF ONLY ONE OF
THE CLASSES OF OUR COMMON STOCK.

         A potential acquirer could acquire control of Acacia Research
Corporation by acquiring shares of common stock having a majority of the voting
power of all shares of common stock outstanding. Such a majority could be
obtained by acquiring a sufficient number of shares of both classes of common
stock or, if one class of common stock has a majority of such voting power, only
shares of that class. Currently, our AR-CombiMatrix stock has a majority of the
voting power. As a result, currently, it might be possible for an acquirer to
obtain control of Acacia Research Corporation by purchasing only shares of
AR-CombiMatrix stock.

DECISIONS BY DIRECTORS AND OFFICERS THAT AFFECT DIFFERENTLY ONE CLASS OF OUR
COMMON STOCK COMPARED TO THE OTHER COULD ADVERSELY AFFECT THE MARKET VALUE OF
EITHER OR BOTH OF THE CLASSES OF OUR COMMON STOCK.

         The relative voting power per share of our AR-CombiMatrix stock and our
AR-Acacia Technologies stock and the number of shares of one class of common
stock issuable upon the conversion of the other class of common stock will vary
depending upon the relative market values of our AR-CombiMatrix stock and our
AR-Acacia Technologies stock. The market value of either or both classes of
common stock could be affected by market reaction to decisions by our board of
directors or our management that investors perceive to affect differently one
class of common stock compared to the other. These decisions could involve
changes to our management and allocation policies, allocations of corporate
opportunities and financing resources between groups, and changes in dividend
policies.

INVESTORS MAY NOT VALUE OUR AR-COMBIMATRIX STOCK AND OUR AR-ACACIA TECHNOLOGIES
STOCK BASED ON GROUP FINANCIAL INFORMATION AND POLICIES.

         We cannot assure you that investors will value our AR-CombiMatrix stock
and our AR-Acacia Technologies stock based on the reported financial results and
prospects of the separate groups or the dividend policies established by our
board of directors with respect to those groups. Holders of AR-CombiMatrix stock
and AR-Acacia Technologies stock will continue to be common stockholders of
Acacia Research Corporation subject to all the risks associated with an
investment in Acacia Research Corporation as a whole. Additionally, the separate
stockholder rights related to each group are limited and relate to events that
may never occur, such as dividend and liquidation rights and the disposition of
all or substantially all of the assets of a group. Accordingly, investors may
discount the value of AR-CombiMatrix stock and AR-Acacia Technologies stock
because both groups are part of a common enterprise rather than a stand-alone
entity and each class of stock has limited separate stockholder rights.

                                       20


HOLDERS OF AR-COMBIMATRIX STOCK AND AR-ACACIA TECHNOLOGIES STOCK MAY NOT RECEIVE
A PREMIUM FROM AN INVESTOR ACQUIRING CONTROL OF THEIR RESPECTIVE CLASSES OF
STOCK.

         Control of AR-CombiMatrix stock or AR-Acacia Technologies stock may not
provide control of Acacia Research Corporation as a whole. Accordingly, unlike
many acquisition transactions, holders of AR-CombiMatrix stock and
AR-Technologies stock may not receive a controlling interest premium from an
investor acquiring control of their respective classes of stock.

THERE ARE CERTAIN PROVISIONS IN OUR TWO-CLASS CAPITAL STRUCTURE THAT COULD HAVE
ANTITAKEOVER EFFECTS.

         The existence of the two classes of common stock could, under certain
circumstances, prevent stockholders from profiting from an increase in the
market value of their shares as a result of a change in control of Acacia
Research Corporation by delaying or preventing such change in control. The
existence of two classes of common stock could present complexities and could,
in certain circumstances, pose obstacles, financial and otherwise, to an
acquiring person. We could, in the sole discretion of our board of directors and
without stockholder approval, exercise the right to convert the shares of one
class of common stock into shares of the other at a 10% premium over their
respective average market values. This conversion could result in additional
dilution to persons seeking control of Acacia Research Corporation.

         Our board of directors could issue shares of preferred stock or common
stock that could be used to create voting or other impediments to discourage
persons seeking to gain control of Acacia Research Corporation, and preferred
stock could also be privately placed with purchasers favorable to our board of
directors in opposing such action.

                                       21


                           FORWARD-LOOKING STATEMENTS

         This prospectus contains forward-looking statements within the meaning
of the federal securities laws. Forward-looking statements are statements that
predict or describe future events or trends and that do not relate solely to
historical matters. You can generally identify forward-looking statements as
statements containing the words "may," "will," "expect," "believe," "estimate,"
"anticipate," "intend," "continue," and other similar expressions or the
negative of these terms. You should be aware that the matters described in our
forward-looking statements are subject to known and unknown risks, uncertainties
and other unpredictable factors, many of which are beyond our control.
Statements regarding the following subjects are forward-looking by their nature:

         o        our business strategies;

         o        market trends and risks;

         o        assumptions regarding economic conditions;

         o        circumstances affecting anticipated revenues and costs; and

         o        legislative, regulatory and competitive developments.

         These forward-looking statements are subject to various risks and
uncertainties, including those related to:

         o        the recent slowdown affecting technology companies;

         o        our ability to successfully develop products;

         o        rapid technological change in our markets;

         o        anticipated sources of future revenues;

         o        changes in demand for our future products;

         o        our ability to raise capital in the future; and

         o        the adequacy of our capital resources to fund our operations.

         Other risks, uncertainties and factors, including those discussed under
"Risk Factors" in this prospectus or described in reports that we file from time
to time with the Securities and Exchange Commission, such as our quarterly and
annual reports, could cause our actual results to differ materially from those
projected in any forward-looking statements we make. We are not obligated to
publicly update or revise any forward-looking statements, whether as a result of
new information, future events or otherwise.

                                 USE OF PROCEEDS

         Unless otherwise indicated in an accompanying prospectus supplement, we
intend to use the net proceeds from the sale of the securities offered by this
prospectus and the related accompanying prospectus supplement to provide working
capital for our business, including our subsidiaries.

                                       22


                        DESCRIPTION OF OUR CAPITAL STOCK

         Following is a summary of the material terms of the AR-CombiMatrix
stock and the AR-Acacia Technologies stock. The summary is not complete and
should be read in conjunction with our restated certificate of incorporation, or
Restated Certificate, filed as Appendix B to the proxy statement/prospectus
which formed a part of our Registration Statement on Form S-4 (SEC File No.
333-87654), which became effective on November 8, 2002.

AUTHORIZED AND OUTSTANDING SHARES

         The Restated Certificate authorizes us to issue 110,000,000 shares of
stock as follows: 50,000,000 shares of a class of common stock, designated as
Acacia Research-CombiMatrix Common Stock (the "AR-CombiMatrix stock"),
50,000,000 shares of a class of common stock, designated as Acacia
Research-Acacia Technologies Common Stock (the "AR-Acacia Technologies stock"),
and 10,000,000 shares of preferred stock. Shares of each class of stock will
have a par value of $0.001 per share. We will be able to issue shares of
preferred stock in series, without stockholder approval.

         As of March 4, 2004, a total of 27,639,201 shares of the AR-CombiMatrix
stock and 19,746,234 shares of the AR-Acacia Technologies stock were issued and
outstanding.

DIVIDENDS

         Dividends on the AR-CombiMatrix stock and dividends on the AR-Acacia
Technologies stock will be limited to an amount not greater than the Available
Dividend Amount (as defined in the Restated Certificate) for the relevant group.
The Available Dividend Amount under our Restated Certificate is essentially the
same as legally available funds under Delaware law, both of which consist of
either the surplus (market value of assets less liabilities and par value) or,
if there is no surplus, the net profits for the fiscal year in which the
dividend is declared and/or the preceding fiscal year.

         In addition, Delaware law limits the amount of distributions on capital
stock to legally available funds as defined under Delaware law, which are
determined on the basis of our entire company, and not only the respective
groups. As a result, the amount of legally available funds will reflect the
amount of any net losses of each group, any distributions on AR-CombiMatrix
stock, AR-Acacia Technologies stock or any preferred stock and any repurchases
of AR-CombiMatrix stock, AR-Acacia Technologies stock or certain preferred
stock. Dividend payments on the AR-CombiMatrix stock and on the AR-Acacia
Technologies stock could be precluded because legally available funds are not
available under Delaware law, even though the Available Dividend Amount test for
the particular relevant group was met. We cannot assure you that there will be
an Available Dividend Amount for either group.

         Subject to the prior payment of dividends on any outstanding shares of
preferred stock and the limitations described above, our board of directors will
be able, in its sole discretion, to declare and pay dividends exclusively on the
AR-CombiMatrix stock, exclusively on the AR-Acacia Technologies stock or on
both, in equal or unequal amounts. In making its dividend decisions, our board
of directors will not be required to take into account the relative Available
Dividend Amounts for the two groups, the amount of prior dividends declared on
either class, the respective voting or liquidation rights of either class or any
other factor.

VOTING RIGHTS

         Under our Restated Certificate the entire voting power of the
stockholders of Acacia Research is vested in the holders of common stock, who
will be entitled to vote on any matter on which the holders of our stock are, by
law or by the provisions of the Restated Certificate, entitled to vote, except
as otherwise provided by law, by the terms of any outstanding preferred stock or
by any provision of the new certificate of incorporation restricting the power
to vote on a specified matter to other stockholders.

                                       23


         Holders of common stock will vote as a single class on each matter on
which holders of common stock are generally entitled to vote.

         On all matters as to which both classes of common stock will vote
together as a single class:

         o        each share of AR-CombiMatrix stock will have one vote; and

         o        each share of AR-Acacia Technologies stock will have a number
                  of votes equal to the quotient of the average market value of
                  a share of AR-Acacia Technologies stock over the 20-trading
                  day period ending on the 10th trading day prior to the record
                  date for determining the holders of common stock entitled to
                  vote, divided by the average market value of a share of
                  AR-CombiMatrix stock over the same period.

         Accordingly, the relative per share voting rights of the AR-CombiMatrix
stock and the AR-Acacia Technologies stock will fluctuate depending on changes
in the relative market values of shares of such classes of common stock. The
purpose of the floating voting power is to link voting power to relative
economic interests in Acacia Research.

   EXAMPLES OF THE CALCULATION OF THE NUMBER OF VOTES EACH SHARE OF AR-ACACIA
          TECHNOLOGIES STOCK WOULD BE ENTITLED ON ALL MATTERS ON WHICH
                  HOLDERS OF AR-COMBIMATRIX STOCK AND AR-ACACIA
                    TECHNOLOGIES STOCK VOTE AS SINGLE CLASS

         EXAMPLE #1: If the average market values for the 20-trading day
valuation period were $4 for the AR-Acacia Technologies stock and $6 for the
AR-CombiMatrix stock, each share of AR-CombiMatrix stock would have one vote and
each share of AR-Acacia Technologies stock would have 0.67 votes based on the
following calculation:

           $4
         ------ =  0.67 votes
           $6

         Based on the assumptions in this example, and assuming 20 million
shares of AR-CombiMatrix stock and 20 million shares of AR-Acacia Technologies
stock were outstanding, the shares of AR-CombiMatrix stock would represent
approximately 60% of our total voting power and the shares of AR-Acacia
Technologies stock would represent approximately 40% of our total voting power.

         EXAMPLE #2: If the average market values for the 20-trading day
valuation period were $5 for the AR-Acacia Technologies stock and $5 for the
AR-CombiMatrix stock, each share of AR-CombiMatrix stock would have one vote and
each share of AR-Acacia Technologies stock would have one (1) vote based on the
following calculation:

           $5
         ------ =  1.0 votes
           $5

         Based on the assumptions in this example, and assuming 20 million
shares of AR-CombiMatrix stock and 20 million shares of AR-Acacia Technologies
stock were outstanding, the shares of AR-CombiMatrix stock would represent
approximately 50% of our total voting power and the shares of AR-Acacia
Technologies stock would represent approximately 50% of our total voting power.

                                       24


         EXAMPLE #3: If the average market values for the 20-trading day
valuation period were $6 for the AR-Acacia Technologies stock and $4 for the
AR-CombiMatrix stock, each share of AR-CombiMatrix stock would have one vote and
each share of AR-Acacia Technologies stock would have 1.50 votes based on the
following calculation:

           $6
         ------ =  1.50 votes
           $4

         Based on the assumptions in this example, and assuming 20 million
shares of AR-CombiMatrix stock and 20 million shares of AR-Acacia Technologies
stock were outstanding, the shares of AR-CombiMatrix stock would represent
approximately 40% of our total voting power and the shares of AR-Acacia
Technologies stock would represent approximately 60% of our total voting power.

         These examples, each of which is based on the assumption that the total
number of issued and outstanding shares of each class is 20,000,000, are
summarized in the table below:



                                        ASSUMED                                            RELATIVE
                                      SHARE PRICE       VOTING RIGHTS     TOTAL VOTES    VOTING POWER
                                      -----------       -------------     -----------    ------------
                                                                                 
EXAMPLE #1:
     AR-CombiMatrix                        $6          1.0 vote/share      20,000,000        60%
     AR-Acacia Technologies                $4         0.67 votes/share     13,333,333        40%

EXAMPLE #2:
     AR-CombiMatrix                        $5          1.0 vote/share      20,000,000        50%
     AR-Acacia Technologies                $5          1.0 vote/share      20,000,000        50%

EXAMPLE #3:
     AR-CombiMatrix                        $4          1.0 vote/share      20,000,000        40%
     AR-Acacia Technologies                $6          1.50 vote/share     30,000,000        60%


         IN THESE EXAMPLES WE HAVE PROVIDED A BETTER UNDERSTANDING OF THE
MECHANICS SURROUNDING THE CALCULATION OF VOTING POWER. IT SHOULD NOT BE ASSUMED
THAT THE EXAMPLES USED ARE IN ANY WAY INDICATIVE OF THE RESPECTIVE COMMON STOCK
TRADING PRICES AT ANY TIME BEFORE OR AFTER THE DATE OF THIS PROSPECTUS.

         We will set forth the number of outstanding shares of AR-CombiMatrix
stock and AR-Acacia Technologies stock in our Annual Reports on Form 10-K and
our Quarterly Reports on Form 10-Q filed under the Securities Exchange Act of
1934, as amended (the "Exchange Act"). We will disclose in any proxy statement
for a stockholders' meeting the number of outstanding shares and per share
voting rights of the AR-CombiMatrix stock and the AR-Acacia Technologies stock.

         If shares of only one class of common stock are outstanding, each share
of that class will have one vote. If either class of common stock is entitled to
vote as a separate class with respect to any matter, each share of that class
will, for purpose of such vote, have one vote on such matter.

         Fluctuations in the relative voting rights of the AR-CombiMatrix stock
and the AR-Acacia Technologies stock could influence an investor interested in
acquiring and maintaining a fixed percentage of the voting power of Acacia
Research to acquire such percentage of both classes of common stock and would
limit the ability of investors in one class to acquire for the same
consideration relatively more or less votes per share than investors in the
other class.

         The holders of AR-CombiMatrix stock and AR-Acacia Technologies stock
will not have any rights to vote separately as a class on any matter coming
before stockholders of Acacia Research, except for certain limited class voting

                                       25


rights provided under Delaware law. In addition to the approval of the holders
of a majority of the voting power of all shares of common stock voting together
as a single class, the approval of a majority of the outstanding shares of the
AR-CombiMatrix stock or the AR-Acacia Technologies stock, voting as a separate
class, would be required under Delaware law to approve any amendment to the
Restated Certificate that would change the par value of the shares of the class
or alter or change the powers, preferences or special rights of the shares of
such class so as to affect them adversely. As permitted by Delaware law, the
Restated Certificate provides that an amendment to the Restated Certificate that
increases or decreases the number of authorized shares of AR-CombiMatrix stock
or AR-Acacia Technologies stock will only require the approval of the holders of
a majority of the voting power of all shares of common stock, voting together as
a single class, and will not require the approval of the holders of the class of
common stock affected by such amendment, voting as a separate class.

CONVERSION AND REDEMPTION

         Our Restated Certificate permits the conversion or redemption of the
AR-CombiMatrix stock and the AR-Acacia Technologies stock as described below.

          MANDATORY DIVIDEND, REDEMPTION OR CONVERSION OF COMMON STOCK
                      IF DISPOSITION OF GROUP ASSETS OCCURS

         If we sell, transfer, assign or otherwise dispose of, in one
transaction or a series of related transactions, all or substantially all of the
properties and assets attributed to either group (a "disposition"), we are
required, except as described below, to:

         o        pay a dividend in cash and/or securities or other property to
                  the holders of shares of the class of common stock relating to
                  the group subject to the disposition having a fair value equal
                  to the net proceeds of the disposition; or

         o        (A) if the disposition involves all, but not merely
                  substantially all, of such properties and assets, redeem all
                  outstanding shares of common stock relating to that group in
                  exchange for cash and/or securities or other property having a
                  fair value equal to the net proceeds of the disposition; or
                  (B) if the disposition involves substantially all, but not
                  all, of such properties and assets, redeem that number of
                  whole shares of the class of common stock relating to that
                  group as have in the aggregate an average market value, during
                  the period of ten consecutive trading days beginning on the
                  26th trading day immediately succeeding the consummation date,
                  closest to the net proceeds of the disposition; and the
                  redemption price will be cash and/or securities or other
                  property having a fair value equal to such net proceeds; or

         o        convert each outstanding share of such class of common stock
                  into a number of shares of common stock relating to the other
                  group equal to 110% of the ratio of the average market value
                  of one share of common stock relating to the group subject to
                  the disposition to the average market value of one share of
                  common stock relating to the other group during the 10-trading
                  day period beginning on the 26th trading day following the
                  disposition date.

         The purpose of this provision is to provide holders of each class of
stock with an economic interest in the proceeds of the disposition of the assets
of the respective group.

         Stockholder approval is typically required for the sale of all or
substantially all of a company's assets. However, we may dispose of all or
substantially all of the assets attributed to either group without stockholder
approval provided those assets do not constitute all or substantially all of the
assets of Acacia Research as a whole.

         We may pay a dividend or redeem shares of common stock as set forth
above only if we have legally available funds under Delaware law and the amount
to be paid to holders is less than or equal to the Available Dividend Amount for
the group. We are required to pay such dividend or complete such redemption or
conversion on or prior to the 95th trading day following the disposition.

                                       26


         For purposes of determining whether a disposition has occurred,
"substantially all of the properties and assets" attributed to either group
means a portion of such properties and assets:

         o        that represents at least 80% of the then fair value of the
                  properties and assets attributed to that group; or

         o        from which were derived at least 80% of the aggregate revenues
                  of that group for the immediately preceding twelve fiscal
                  quarterly periods.

         The "net proceeds" of a disposition means an amount equal to what
remains of the gross proceeds of the disposition after any payment of, or
reasonable provision is made as determined by our board of directors for:

         o        any taxes payable by us, or which would have been payable but
                  for the utilization of tax benefits attributable to the group
                  not subject to the disposition, in respect of the disposition
                  or in respect of any resulting dividend or redemption;

         o        any transaction costs, including, without limitation, any
                  legal, investment banking and accounting fees and expenses;
                  and

         o        any liabilities of or attributed to the group subject to the
                  disposition, including, without limitation, any liabilities
                  for deferred taxes, any indemnity or guarantee obligations
                  incurred in connection with the disposition or otherwise, any
                  liabilities for future purchase price adjustments and any
                  preferential amounts plus any accumulated and unpaid dividends
                  in respect of the preferred stock attributed to that group.

         We may elect to pay the dividend or redemption price in connection with
a disposition either in the same form as the proceeds of the disposition were
received or in any other combination of cash, securities or other property that
our board of directors or, in the case of securities that have not been publicly
traded for a period of at least 15 months, an independent investment banking
firm, determines will have an aggregate market value of not less than the fair
value of the net proceeds.

              EXAMPLE OF PROVISIONS REQUIRING A MANDATORY DIVIDEND,
                REDEMPTION OR CONVERSION IF A DISPOSITION OCCURS

         If (1) 20 million shares of AR-CombiMatrix stock and 20 million shares
of AR-Acacia Technologies stock were outstanding, (2) the net proceeds of the
disposition of substantially all, but not all, of the assets of the Acacia
Technologies group equals $80 million, (3) the average market value of the
AR-Acacia Technologies stock during the 10-trading day valuation period was $4
per share and (4) the average market value of the AR-CombiMatrix stock during
the same valuation period was $8 per share, then we could do any of the
following:



                                                                             
         (1)      pay a dividend to the holders of shares of AR-Acacia
                  Technologies stock equal to:

                                          Net Proceeds
                  ------------------------------------------------------------  =  Amount per share
                  Number of Outstanding Shares of AR-Acacia Technologies stock

                                          $80 million
                  ------------------------------------------------------------  =  $4 per share
                                       20 million shares


                                       27




                                                                             
         (2)      redeem for $4 per share a number of shares of AR Acacia
                  Technologies stock equal to:

                                        Net Proceeds
                  ------------------------------------------------------------  =  Number of Shares
                    Average Market Value of AR-Acacia Technologies stock

                                        $80 million
                  ------------------------------------------------------------  =  20,000,000 shares
                                        $4 per share

         (3)      convert each outstanding share of AR-Acacia Technologies stock
                  into a number of shares of AR-CombiMatrix stock equal to:

                              Average Market Value of AR-Acacia Technologies stock
                  1.1   X   --------------------------------------------------------  =  Number of Shares
                                 Average Market Value of AR-CombiMatrix stock

                                              $4 per share
                  1.1   X   --------------------------------------------------------  =  0.55 shares
                                              $8 per share


         IN THESE EXAMPLES WE HAVE PROVIDED A BETTER UNDERSTANDING OF THE
MECHANICS SURROUNDING THE CALCULATION OF VOTING POWER. IT SHOULD NOT BE ASSUMED
THAT THE EXAMPLES USED ARE IN ANY WAY INDICATIVE OF THE RESPECTIVE COMMON STOCK
TRADING PRICES AT ANY TIME BEFORE OR AFTER THE DATE OF THIS PROSPECTUS.

        EXCEPTIONS TO THE DIVIDEND, REDEMPTION AND CONVERSION REQUIREMENT
                             IF A DISPOSITION OCCURS

         We are not required to take any of the above actions for any
disposition of all or substantially all of the properties and assets attributed
to either group in a transaction or series of related transactions that results
in our receiving for such properties and assets primarily equity securities of
any entity that:

         (1)      acquires such properties or assets, succeeds to the business
                  conducted with such properties or assets, or controls such
                  acquirer or successor; and

         (2)      engages primarily or proposes to engage primarily in one or
                  more businesses similar or complementary to the businesses
                  conducted by that group prior to the disposition, as
                  determined by our board of directors.

         The purpose of the exception is to enable us technically to "dispose"
of properties or assets of a group to other entities engaging or proposing to
engage in businesses similar or complementary to those of that group without
requiring a dividend on, or a conversion or redemption of, the class of common
stock of that group, so long as we hold an equity interest in that entity. A
joint venture in which we own a direct or indirect equity interest is an example
of such an acquirer. We are not required to control that entity, whether by
ownership or contract provisions.

         We are also not required to effect a dividend, redemption or conversion
if the disposition is:

         o        of all or substantially all of our properties and assets in
                  one transaction or a series of related transactions in
                  connection with our dissolution, liquidation or winding up and
                  the distribution of our assets to stockholders;

         o        on a pro rata basis, such as in a spin-off, to the holders of
                  all outstanding shares of the class of common stock relating
                  to the group subject to the disposition; or

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         o        made to any person or entity controlled by us, as determined
                  by our board of directors.

                 NOTICES IF A DISPOSITION OF GROUP ASSETS OCCURS

         Not later than the 20th trading day after the consummation of a
disposition, we will announce publicly by press release:

         o        the estimated net proceeds of the disposition;

         o        the number of shares outstanding of the class of common stock
                  relating to the group subject to the disposition; and

         o        the number of shares of such class of common stock into or for
                  which convertible securities are then convertible,
                  exchangeable or exercisable and the conversion, exchange or
                  exercise price thereof.

         Not earlier than the 36th trading day and not later than the 40th
trading day after the consummation of the disposition, we will announce publicly
by press release whether we will pay a dividend or redeem shares of common stock
with the net proceeds of the disposition or convert the shares of common stock
of the group subject to the disposition into the other class of common stock.

         We are required to cause to be mailed to each holder of shares of the
class of common stock relating to the group subject to the disposition the
additional notices and other information required by the Restated Certificate.

                             DESCRIPTION OF WARRANTS

         We have warrants to purchase 358,410 shares of our AR-CombiMatrix stock
outstanding and no warrants to purchase our AR-Acacia Technologies stock
outstanding, other than options issued under our 2002 CombiMatrix Stock
Incentive Plan and our 2002 Acacia Technologies Stock Incentive Plan, as
applicable. We may in the future issue warrants for the purchase of our
AR-CombiMatrix stock or our AR-Acacia Technologies stock. Warrants may be issued
independently, together with any other securities offered by any prospectus
supplement or through a dividend or other distribution to our stockholders and
may be attached to or separate from the related securities. Warrants may be
issued under a warrant agreement to be entered into between us and a warrant
agent specified in the applicable prospectus supplement. The warrant agent will
act solely as our agent in connection with the warrants of a particular series
and will not assume any obligation or relationship of agency or trust for or
with any holders or beneficial owners of warrants. The following sets forth
certain general terms and provisions of the warrants that may be offered under
this prospectus. The applicable warrant agreement and form of warrant
certificate will be filed as exhibits to or incorporated by reference in the
registration statement. Further terms of the warrants and the applicable warrant
agreement will be set forth in the applicable prospectus supplement.

         The applicable prospectus supplement will describe the terms of the
warrants in respect of which this prospectus is being delivered, including,
where applicable, the following: (a) the title of the warrants; (b) the
aggregate number of the warrants; (c) the price or prices at which the warrants
will be issued; (d) the designation, number and terms of the shares of our
AR-CombiMatrix stock or our AR-Acacia Technologies stock purchasable upon
exercise of the warrants; (e) the designation and terms of the other securities,
if any, with which the warrants are issued and the number of the warrants issued
with each security; (f) the date, if any, on and after which the warrants and
the related AR-CombiMatrix stock or AR-Acacia Technologies stock, if any, will
be separately transferable; (g) the price at which each share of AR-CombiMatrix
stock or AR-Acacia Technologies stock purchasable upon exercise of the warrants
may be purchased; (h) the date on which the right to exercise the warrants will
commence and the date on which that right will expire; (i) the minimum or
maximum amount of the warrants which may be exercised at any one time; (j)
information with respect to book-entry procedures, if any; (k) a discussion of
federal income tax considerations; and (l) any other terms of the warrants,
including terms, procedures and limitations relating to the transferability,
exchange and exercise of the warrants.

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                              PLAN OF DISTRIBUTION

         We may sell the securities offered pursuant to this prospectus and any
accompanying prospectus supplements to or through one or more underwriters or
dealers or we may sell the securities to investors directly or through agents.
Each prospectus supplement will describe the number and terms of the securities
to which such prospectus supplement relates, the name or names of any
underwriters or agents with whom we have entered into arrangements with respect
to the sale of such securities, the public offering or purchase price of such
securities and the net proceeds we will receive from such sale. Any underwriter
or agent involved in the offer and sale of the securities will be named in the
applicable prospectus supplement. We may sell securities directly to investors
on our own behalf in those jurisdictions where we are authorized to do so.

         Underwriters may offer and sell the securities at a fixed price or
prices, which may be changed, at market prices prevailing at the time of sale,
at prices related to the prevailing market prices or at negotiated prices. We
also may, from time to time, authorize dealers or agents to offer and sell these
securities upon such terms and conditions as may be set forth in the applicable
prospectus supplement. In connection with the sale of any of these securities,
underwriters may receive compensation from us in the form of underwriting
discounts or commissions and may also receive commissions from purchasers of the
securities for whom they may act as agent. Underwriters may sell the securities
to or through dealers, and such dealers may receive compensation in the form of
discounts, concessions or commissions from the underwriters or commissions from
the purchasers for which they may act as agents. The maximum compensation or
discount to be received by any member of the National Association of Securities
Dealers or any independent broker-dealer will not be greater than 8% for the
sale of any securities registered pursuant Rule 415 under the Securities Act of
1933.

         Shares may also be sold in one or more of the following transactions:
(a) block transactions (which may involve crosses) in which a broker-dealer may
sell all or a portion of the shares as agent but may position and resell all or
a portion of the block as principal to facilitate the transaction; (b) purchases
by a broker-dealer as principal and resale by the broker-dealer for its own
account pursuant to a prospectus supplement; (c) a special offering, an exchange
distribution or a secondary distribution in accordance with applicable Nasdaq
National Market or other stock exchange rules; (d) ordinary brokerage
transactions and transactions in which a broker-dealer solicits purchasers; (e)
sales "at the market" to or through a market maker or into an existing trading
market, on an exchange or otherwise, for shares; and (f) sales in other ways not
involving market makers or established trading markets, including direct sales
to purchasers. Broker-dealers may also receive compensation from purchasers of
the shares which is not expected to exceed that customary in the types of
transactions involved.

         Any underwriting compensation paid by us to underwriters or agents in
connection with the offering of these securities, and any discounts or
concessions or commissions allowed by underwriters to participating dealers,
will be set forth in the applicable prospectus supplement. Dealers and agents
participating in the distribution of the securities may be deemed to be
underwriters, and any discounts and commissions received by them and any profit
realized by them on resale of the securities may be deemed to be underwriting
discounts and commissions.

         Underwriters, dealers and agents may be entitled, under agreements
entered into with us, to indemnification against and contribution toward certain
civil liabilities, including liabilities under the Securities Act of 1933.
Unless otherwise set forth in the accompanying prospectus supplement, the
obligations of any underwriters to purchase any of these securities will be
subject to certain conditions precedent, and the underwriters will be obligated
to purchase all of the series of securities, if any are purchased.

         Underwriters, dealers and agents may engage in transactions with, or
perform services for, us and our affiliates in the ordinary course of business.

         In connection with offering securities pursuant to this prospectus,
certain underwriters, and selling group members and their respective affiliates,
may engage in transactions that stabilize, maintain or otherwise affect the
market price of the applicable securities. These transactions may include
stabilization transactions effected in accordance with Rule 104 of Regulation M
promulgated by the SEC pursuant to which these persons may bid for or purchase
securities for the purpose of stabilizing their market price.

                                       30


         The underwriters in an offering of securities may also create a "short
position" for their account by selling more securities in connection with the
offering than they are committed to purchase from us. In that case, the
underwriters could cover all or a portion of the short position by either
purchasing securities in the open market following completion of the offering of
these securities or by exercising any over-allotment option granted to them by
us. In addition, the managing underwriter may impose "penalty bids" under
contractual arrangements with other underwriters, which means that they can
reclaim from an underwriter (or any selling group member participating in the
offering) for the account of the other underwriters, the selling concession for
the securities that are distributed in the offering but subsequently purchased
for the account of the underwriters in the open market. Any of the transactions
described in this paragraph or comparable transactions that are described in any
accompanying prospectus supplement may result in the maintenance of the price of
the securities at a level above that which might otherwise prevail in the open
market. None of the transactions described in this paragraph or in an
accompanying prospectus supplement are required to be taken by any underwriters
and, if they are undertaken, may be discontinued at any time.

         The AR-CombiMatrix stock is listed on the Nasdaq National Market under
the symbol "CBMX". The AR-Acacia Technologies stock is listed on the Nasdaq
National Market under the symbol "ACTG". Any underwriters or agents to or
through which securities are sold by us may make a market in the securities, but
these underwriters or agents will not be obligated to do so and any of them may
discontinue any market making at any time without notice. No assurance can be
given as to the liquidity of or trading market for any securities sold by us.

                                     EXPERTS

         The financial statements incorporated in this prospectus by reference
to the Annual Report on Form 10-K of Acacia Research Corporation for the year
ended December 31, 2003, have been so incorporated in reliance on the report of
PricewaterhouseCoopers LLP, independent accountants, given on the authority of
said firm as experts in auditing and accounting.

                                  LEGAL MATTERS

         The validity of our securities offered in this prospectus will be
passed upon for us by Allen Matkins Leck Gamble & Mallory LLP, Century City,
California.

                       WHERE YOU CAN FIND MORE INFORMATION

         We file annual, quarterly and special reports, proxy statements and
other information with the SEC. You may read and copy the materials we file at
the SEC's Public Reference Room at 450 Fifth Street, N.W., Washington D.C.
20549. Please call the SEC at 1-800-SEC-0330 for further information on the
operation of the Public Reference Rooms. Our SEC filings are also available to
the public from the SEC's World Wide Web site on the Internet at
http://www.sec.gov. This site contains reports, proxy and information statements
and other information regarding issuers that file electronically with the SEC.
You may also read and copy this information at the National Association of
Securities Dealers, Inc., 1735 K Street, N.W., Washington D.C. 20006.

         We maintain a site on the Internet at http://www.acaciaresearch.com.
The information contained in our website is not part of this prospectus and you
should not rely on it in deciding whether to invest in our common stock.

         We have filed a registration statement, of which this prospectus is a
part, covering the offered securities. As allowed by SEC rules, this prospectus
does not include all of the information contained in the registration statement
and the included exhibits, financial statements and schedules. We refer you to
the registration statement, the included exhibits, financial statements and
schedules for further information. This prospectus is qualified in its entirety
by such other information.

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                      INFORMATION INCORPORATED BY REFERENCE

         The SEC allows us to "incorporate by reference" the information that we
file with the SEC. This means that we can disclose important information to you
by referring you to another document filed separately with the SEC under the
Exchange Act. The information incorporated by reference is deemed to be part of
this prospectus, except for any information superseded by information in this
prospectus. We have filed with the SEC and incorporate by reference:

         o        our annual report on Form 10-K for the fiscal year ended
                  December 31, 2003;

         o        the description of the AR-CombiMatrix stock and the AR-Acacia
                  Technologies stock included in our registration statement on
                  Form 8-A.

         Any documents we file pursuant to Section 13(a), 13(c), 14 or 15(d) of
the Exchange Act after the date of this prospectus and prior to the termination
of the offering of the securities to which this prospectus relates will
automatically be deemed to be incorporated by reference in this prospectus and
to be part hereof from the date of filing those documents. Any statement
contained in this prospectus or in a document incorporated by reference shall be
deemed to be modified or superseded for all purposes to the extent that a
statement contained in this prospectus or in any other document which is also
incorporated by reference modifies or supersedes that statement.

         We will provide without charge to each person to whom a copy of this
prospectus is delivered, upon such person's written or oral request, a copy of
any and all of the information incorporated by reference in this prospectus,
other than exhibits to such documents, unless such exhibits are specifically
incorporated by reference into the information that this prospectus
incorporates. Requests should be directed to the Secretary at Acacia Research
Corporation, 500 Newport Center Drive, 7th Floor, Newport Beach, California
92660, telephone: (949) 480-8300.

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