QUESTIONS AND ANSWERS

        The following are answers to some questions that you, as a stockholder of Cousins or a stockholder of TIER, may have regarding the proposed business combination of Cousins and TIER and the other matters being considered at the special meeting of Cousins and at the special meeting of TIER. Cousins and TIER urge you to carefully read the entirety of this joint proxy statement/prospectus because the information in this section does not provide all the information that might be important to you with respect to the proposed transaction and the other matters being considered at the special meetings. Additional important information is also contained in the annexes to and the documents incorporated by reference into this joint proxy statement/prospectus.

Q:

What is the Merger?

A:

Cousins and TIER have agreed to a business combination under the terms of the Merger Agreement, pursuant to which TIER will merge with and into Merger Sub (which we refer to as the "Merger"), with Merger Sub continuing as the surviving corporation. A copy of the Merger Agreement is attached as Annex A to this joint proxy statement/prospectus.

In connection with the Merger, each TIER common stockholder will have the right to receive 2.98 newly issued shares of Cousins common stock for each share of TIER common stock, par value $.0001 per share (which we refer to as "TIER common stock"), that they own immediately prior to the effective time of the Merger (which we refer to as the "exchange ratio"), subject to customary anti-dilution adjustments and with cash paid in lieu of fractional shares.

Q:

What happens if the market price of shares of Cousins common stock or TIER common stock changes before the closing of the Merger?

A:

No change will be made to the exchange ratio if the market price of shares of Cousins common stock or TIER common stock changes before the Merger. Because the exchange ratio is fixed, other than customary anti-dilution adjustments in the event of certain changes in Cousins' capitalization, the value of the consideration to be received by TIER stockholders in the Merger will depend on the market price of shares of Cousins common stock at the time of the Merger.

Q:

Why am I receiving this joint proxy statement/prospectus?

A:

The Merger cannot be completed, unless:

•

the holders of Cousins common stock vote to approve the issuance of Cousins common stock to TIER stockholders in connection with the Merger (which we refer to as the "Cousins Issuance Proposal"); and

•

the holders of TIER common stock vote to approve the Merger on the terms and subject to the conditions set forth in the Merger Agreement (which we refer to as the "TIER Merger Proposal").

Each of Cousins and TIER will hold separate special meetings of their stockholders to obtain these approvals and approvals for other related proposals as described herein.

This joint proxy statement/prospectus contains important information about the Merger and the other proposals being voted on at the special meetings, and you should read it carefully. It is a joint proxy statement because the Cousins board of directors is soliciting proxies from its stockholders and the TIER board of directors is soliciting proxies from its stockholders. It is a prospectus because Cousins will issue shares of its common stock. The enclosed voting materials allow you to vote your shares without attending your respective meeting.

Your vote is important. We encourage you to vote as soon as possible.

Q:

Why is Cousins proposing the Merger?

A:

Among other reasons, the Cousins board of directors unanimously approved the Merger Agreement and recommended the approval of the Cousins Issuance Proposal based on a number of strategic and financial benefits to Cousins, including the potential for Cousins, following the Merger, to be the preeminent Sun Belt office real estate investment trust (which we refer to as a "REIT") with a portfolio of trophy office properties in the premier submarkets of Atlanta, Austin, Charlotte, Dallas, Phoenix and Tampa. For more information, see "The Merger—Cousins' Reasons for the Merger; Recommendations of the Cousins Board of Directors."

Q:

Why is TIER proposing the Merger?

A:

Among other reasons, the TIER board of directors unanimously approved the Merger Agreement and the Merger and recommended approval of the Merger by TIER stockholders based on a number of strategic and financial benefits, including the potential for Cousins to create additional value for TIER stockholders due to its larger size and stronger balance sheet and the premium TIER stockholders will receive in the Merger. For more information, see "The Merger—TIER's Reasons for the Merger; Recommendations of the TIER Board of Directors."

Q:

When and where will the special meetings be held?

A:

The Cousins special meeting will be held at            on            , 2019, at            , local time. The TIER special meeting will be held at             , on            , 2019, at            , local time.

Q:

How do I vote?

A:

Cousins.    If you are a holder of record of Cousins common stock or Cousins preferred stock as of the record date for the Cousins special meeting, you may vote by:

•

accessing the Internet website specified on your proxy card;

•

calling the toll-free number specified on your proxy card;

•

signing and returning the enclosed proxy card in the postage-paid envelope provided; or

•

attending the Cousins special meeting in person.

If you hold Cousins common stock or Cousins preferred stock in the name of a broker, bank or nominee, please follow the voting instructions provided by your broker, bank or nominee to ensure that your shares are represented at your special meeting. Street name holders may only vote in person if they have a legal proxy to vote their shares.

TIER.    If you are a holder of record of TIER common stock as of the record date for the TIER special meeting, you may vote on the applicable proposals by:

•

accessing the Internet website specified on your proxy card;

•

calling the toll-free number specified on your proxy card;

•

signing and returning the enclosed proxy card in the postage-paid envelope provided; or

•

attending the TIER special meeting in person.

If you hold shares of TIER common stock in the name of a broker, bank or nominee, please follow the voting instructions provided by your broker, bank or nominee to ensure that your shares are represented at your special meeting. Street name holders may only vote in person if they have a legal proxy to vote their shares.

Q:

What am I being asked to vote upon?

A:

Cousins.    Cousins stockholders are being asked to vote to approve the Cousins Issuance Proposal. Cousins stockholders are also being asked to vote to approve a proposal to amend the amended and restated articles of incorporation of Cousins (which we refer to as the "Cousins Articles") to effect a one-for-four reverse stock split of the Cousins common stock (which we refer to as the "Cousins Reverse Stock Split Proposal"), to approve a proposal to amend the Cousins Articles, to increase the number of authorized shares of Cousins common stock (which we refer to as the "Cousins Authorized Share Count Proposal") and to approve a proposal to adjourn the Cousins special meeting, if necessary or appropriate, to solicit additional proxies in favor of the Cousins Issuance Proposal, the Cousins Reverse Stock Split Proposal or the Cousins Authorized Share Count Proposal if there are insufficient votes at the time of such adjournment to approve such proposals (which we refer to as the "Cousins Adjournment Proposal").

TIER.    Holders of TIER common stock are being asked to vote to approve the TIER Merger Proposal. Holders of TIER common stock are also being asked to approve, by advisory (nonbinding) vote, the compensation that may be paid or become payable to the named executive officers of TIER in connection with the Merger (which we refer to as the "TIER Compensation Proposal") and to approve a proposal to adjourn the TIER special meeting, if necessary or appropriate, to solicit additional proxies in favor of the TIER Merger Proposal, if there are insufficient votes at the time of such adjournment to approve such proposals (which we refer to as the "TIER Adjournment Proposal").

The Merger cannot be completed without the approval by Cousins stockholders of the Cousins Issuance Proposal and the approval by TIER common stockholders of the TIER Merger Proposal.

Q:

What vote is required to approve each proposal?

A:

Cousins.

•

The Cousins Issuance Proposal requires the affirmative vote of the majority of the votes cast by Cousins common stockholders, assuming a quorum is present.

•

The Cousins Reverse Stock Split Proposal requires the affirmative vote of the holders of a majority of the outstanding shares of Cousins common stock and Cousins preferred stock, voting together as a single class, assuming a quorum is present.

•

The Cousins Authorized Share Count Proposal requires the affirmative vote of the holders of a majority of the outstanding shares of Cousins common stock and Cousins preferred stock, voting together as a single class, assuming a quorum is present.

•

The Cousins Adjournment Proposal requires the affirmative vote of the holders of a majority of the shares of Cousins common stock represented, in person or by proxy, at the Cousins special meeting and entitled to vote on the proposal, whether or not a quorum is present.

TIER.

•

The TIER Merger Proposal requires the affirmative vote of the holders of TIER common stock entitled to cast a majority of all of the votes entitled to be cast on the Merger.

•

The TIER Compensation Proposal requires the affirmative vote of the majority of the votes cast by holders of TIER common stock, assuming a quorum is present; however, such vote is advisory (nonbinding) only.

•

The TIER Adjournment Proposal requires the affirmative vote of the majority of the votes cast by holders of TIER common stock, whether or not a quorum is present.

Q:

How do the boards of directors of Cousins and TIER recommend that I vote?

A:

Cousins.    The Cousins board of directors unanimously recommends that holders of Cousins common stock vote "FOR" the Cousins Issuance Proposal, that holders of Cousins common stock and Cousins preferred stock vote "FOR" the Cousins Reverse Stock Split Proposal and "FOR" the Cousins Authorized Share Count Proposal and that holders of Cousins common stock vote "FOR" the Cousins Adjournment Proposal.

TIER.    The TIER board of directors unanimously recommends that holders of TIER common stock vote "FOR" the TIER Merger Proposal, "FOR" the TIER Compensation Proposal and "FOR" the TIER Adjournment Proposal.

Q:

How many votes do I have?

A:

Cousins.    You are entitled to one vote for each share of Cousins common stock or Cousins preferred stock that you owned as of the close of business on the record date. As of the close of business on            , 2019, the record date for the Cousins special meeting, there were             outstanding shares of Cousins common stock, approximately            % of which were beneficially owned by the directors and executive officers of Cousins, and            outstanding shares of Cousins preferred stock, approximately            % of which were beneficially owned by the directors and executive officers of Cousins. Holders of Cousins preferred stock are not entitled to vote on the Cousins Issuance Proposal or the Cousins Adjournment Proposal.

TIER.    You are entitled to one vote for each share of TIER common stock that you owned as of the close of business on the record date. As of the close of business on            , 2019, the record date for the TIER special meeting, there were            outstanding shares of TIER common stock,            % of which were beneficially owned by the directors and executive officers of TIER.

Q:

What constitutes a quorum?

A:

Cousins.    Stockholders who hold a majority of the Cousins common stock outstanding on the record date and who are entitled to vote must be present or represented by proxy to constitute a quorum at the Cousins special meeting.

TIER.    Stockholders entitled to cast a majority of all votes entitled to be cast must be present in person or represented by proxy to constitute a quorum at the TIER special meeting.

Q:

If my shares of common stock (or, if applicable, Cousins preferred stock) are held in "street name" by my broker, will my broker vote my shares for me?

A:

If you hold your shares in a stock brokerage account or if your shares are held by a bank or nominee (that is, in "street name"), you must provide the record holder of your shares with instructions on how to vote your shares of common stock. Please follow the voting instructions provided by your broker, bank or nominee. Please note that you may not vote shares held in street name by returning a proxy card directly to Cousins or TIER or by voting in person at either special meeting unless you provide a "legal proxy," which you must obtain from your broker, bank or nominee. Further, brokers who hold shares of Cousins common stock, Cousins preferred stock or TIER common stock on behalf of their customers may not give a proxy to Cousins or TIER to vote those shares without specific instructions from their customers.

Q:

What will happen if I fail to instruct my broker, bank or nominee how to vote?

A:

Cousins.    If you are a Cousins stockholder and you do not instruct your broker, bank or nominee on how to vote your shares of common stock, your broker may not vote your shares on the Cousins Issuance Proposal, the Cousins Reverse Stock Split Proposal, the Cousins Authorized

Share Count Proposal or the Cousins Adjournment Proposal. This will have the same effect as a vote against the Cousins Reverse Stock Split Proposal and the Cousins Authorized Share Count Proposal, and will have no effect on the Cousins Issuance Proposal, assuming a quorum is present, or the Cousins Adjournment Proposal.

TIER.    If you are a TIER stockholder and you fail to instruct your broker, bank or nominee to vote your shares of TIER common stock, as applicable, your broker may not vote your shares on the TIER Merger Proposal, the TIER Compensation Proposal or the TIER Adjournment Proposal. This will have the same effect as a vote against the TIER Merger Proposal, but it will have no effect on the TIER Compensation Proposal, assuming a quorum is present, or the TIER Adjournment Proposal.

Q:

What will happen if I fail to vote or I abstain from voting?

A:

Cousins.    If you are a Cousins stockholder and fail to vote or abstain from voting, it will have the same effect as a vote against the Cousins Reverse Stock Split Proposal and the Cousins Authorized Share Count Proposal, but it will have no effect on the Cousins Issuance Proposal, assuming a quorum is present, or the Cousins Adjournment Proposal.

TIER.    If you are a TIER stockholder and fail to vote or abstain from voting, it will have the same effect as a vote against the TIER Merger Proposal, but it will have no effect on the TIER Compensation Proposal, assuming a quorum is present, or the TIER Adjournment Proposal.

Q:

What if I return my proxy card without indicating how to vote?

A:

If you sign and return your proxy card without indicating how to vote on any particular proposal, your shares of Cousins common stock, Cousins preferred stock or TIER common stock will be voted in accordance with the recommendation of the Cousins board of directors or TIER board of directors, as applicable, with respect to such proposal.

Q:

Can I change my vote after I have returned a proxy or voting instruction card?

A:

Yes. You can change your vote at any time before your proxy is voted at your special meeting. You can do this in one of three ways:

•

you can send a signed notice of revocation;

•

you can grant a new, valid proxy bearing a later date; or

•

if you are a holder of record, you can attend the Cousins special meeting or the TIER special meeting, as applicable, and vote in person, which will automatically cancel any proxy previously given, or you may revoke your proxy in person, but your attendance alone will not revoke any proxy that you have previously given.

Attending the Cousins special meeting or the TIER special meeting without voting will not, by itself, revoke your proxy. If your shares of Cousins common stock or TIER common stock are held by a bank, broker or nominee, you should follow the instructions provided by the bank, broker or nominee.

If you choose either of the first two methods, you must submit your notice of revocation or your new proxy to the secretary of Cousins or secretary of TIER, as appropriate, no later than the beginning of the applicable special meeting. If your shares of Cousins common stock or TIER common stock are held in street name by your broker, bank or nominee, you should contact your broker, bank or nominee to change your vote.

Q:

What are the material U.S. federal income tax consequences of the Merger to U.S. holders of TIER common stock?

A:

TIER and Cousins intend for the Merger to qualify as a "reorganization" within the meaning of Section 368(a) of the Internal Revenue Code of 1986, as amended (which we refer to as the "Code"). The obligation of the parties to consummate the Merger is subject to the receipt by Cousins and TIER of the opinions of their respective counsels to the effect that, on the basis of facts, representations and assumptions set forth in such opinions, the Merger will qualify as a "reorganization" within the meaning of Section 368(a) of the Code. Accordingly, on the basis of the opinions described above, a U.S. holder of TIER common stock generally will not recognize any gain or loss upon receipt of shares of Cousins common stock in exchange for TIER common stock in the Merger (other than gain or loss with respect to cash received in lieu of a fractional share of Cousins common stock, if any).

The particular consequences of the Merger to each TIER stockholder depend on such holder's particular facts and circumstances. TIER stockholders are urged to consult their tax advisors to understand fully the consequences to them of the Merger in their specific circumstances. For more information, see "Material U.S. Federal Income Tax Consequences of the Merger."

Q:

Are there any conditions to closing of the Merger that must be satisfied for the Merger to be completed?

A:

Yes. In addition to the approval of the Cousins Issuance Proposal and TIER Merger Proposal, there are a number of conditions that must be satisfied or waived for the Merger to be consummated. For more information, see "The Merger—The Merger Agreement—Conditions to Completion of the Merger."

Q:

When do you expect the Merger to be completed?

A:

Cousins and TIER are working to complete the Merger by the third quarter of 2019. However, the Merger is subject to various conditions, and it is possible that factors outside the control of Cousins and TIER could result in the Merger being completed at a later time, or not at all. There may be a substantial amount of time between the respective Cousins special meeting and TIER special meeting and the completion of the Merger. Cousins and TIER hope to complete the Merger as soon as reasonably practicable following the satisfaction of all applicable conditions.

Q:

Are TIER and Cousins stockholders entitled to appraisal rights in connection with the Merger?

A:

No. Holders of TIER common stock will not be entitled to appraisal rights or dissenters' rights in the Merger under Section 3-202 of the Maryland General Corporation Law (which we refer to as the "MGCL") because TIER common stock is listed on a national securities exchange. Under Section 14-2-1302 of the Georgia Business Corporations Code (which we refer to as the "GBCC"), holders of Cousins common stock do not have the right to receive the appraised value of their shares in connection with the Merger. For more information, see "The Merger—No Appraisal or Dissenters' Rights."

Q:

What do I need to do now?

A:

Carefully read and consider the information contained in and incorporated by reference into this joint proxy statement/prospectus, including its annexes.

In order for your shares to be voted at the Cousins special meeting or the TIER special meeting:

•

you can attend the applicable special meeting in person;

•

you can vote through the Internet or by telephone by following the instructions included on your proxy card; or



•

you can indicate on the enclosed proxy or voting instruction card how you would like to vote and return the card in the accompanying postage-paid envelope.

Q:

Do I need to do anything with my share certificates now?

A:

TIER.    No.    You should not submit your share certificates at this time. After the Merger is completed, if you held certificates representing TIER common stock immediately prior to the effective time of the Merger,            , the exchange agent for Cousins (which we refer to as the "exchange agent"), will send you a letter of transmittal and instructions for exchanging your shares of TIER common stock for the Merger consideration equal to the exchange ratio. Upon surrender of the certificates for cancellation along with the executed letter of transmittal and other required documents described in the instructions, a holder of shares of TIER common stock will receive the Merger consideration equal to the exchange ratio.

Holders of shares of TIER common stock in book-entry form immediately prior to the effective time of the Merger will not need to take any action to receive the Merger consideration equal to the exchange ratio.

Cousins.    If you are a Cousins stockholder, you are not required to take any action with respect to your Cousins stock certificates. Such certificates will continue to represent shares of Cousins after the Merger.

Q:

Do I need identification to attend the Cousins or TIER special meetings in person?

A:

Yes. Please bring proper identification, together with proof that you are a record owner of Cousins common stock or Cousins preferred stock or TIER common stock. If your shares are held in street name, please bring acceptable proof of ownership, such as a letter from your broker or an account statement stating or showing that you beneficially owned shares of Cousins common or preferred stock or TIER common stock, as applicable, on the applicable record date.

Q:

Who can help answer my questions?

A:

Cousins stockholders or TIER stockholders who have questions about the Merger or the other matters to be voted on at the special meetings or who desire additional copies of this joint proxy statement/prospectus or additional proxy or voting instruction cards should contact:

SUMMARY

        This summary highlights information contained elsewhere in this joint proxy statement/prospectus and may not contain all of the information that is important to you. Cousins and TIER urge you to read carefully this joint proxy statement/prospectus, including the attached annexes, and the other documents to which we have referred you because this section does not provide all of the information that might be important to you with respect to the Merger and the related matters being considered at the applicable special meeting. See also "Where You Can Find More Information." We have included page references to direct you to a more complete description of the topics presented in this summary.

Information about the Companies

Cousins Properties Incorporated (See page 35)

        Cousins, a Georgia corporation, is a fully integrated, self-administered and self-managed real estate investment trust. Cousins, based in Atlanta, Georgia and acting through its operating partnership, Cousins Properties LP, primarily invests in Class A office towers located in high-growth Sun Belt markets. Founded in 1958, Cousins creates stockholder value through its extensive expertise in the development, acquisition, leasing and management of high-quality real estate assets. Cousins has a comprehensive strategy in place based on a simple platform, trophy assets and opportunistic investments.

        The principal offices of Cousins are located at 3344 Peachtree Street NE, Suite 1800, Atlanta, Georgia 30326, and its telephone number is (404) 407-1000.

        Cousins common stock is listed on the New York Stock Exchange (which we refer to as the "NYSE"), trading under the symbol "CUZ."

        Additional information about Cousins and its subsidiaries is included in documents incorporated by reference into this joint proxy statement/prospectus. For more information, see "Where You Can Find More Information."

Murphy Subsidiary Holdings Corporation (See page 35)

        Merger Sub, a Maryland corporation, is a direct, wholly owned subsidiary of Cousins. Merger Sub was formed by Cousins solely for the purpose of engaging in the transactions contemplated by the Merger Agreement. Merger Sub has not conducted any business activities, has no assets, liabilities or obligations and has conducted its operations solely as contemplated by the Merger Agreement.

        Merger Sub's principal offices are located at c/o Cousins Properties Incorporated, 3344 Peachtree Street NE, Suite 1800, Atlanta, Georgia 30326, and its telephone number is (404) 407-1000.

TIER REIT, Inc. (See page 35)

        TIER, a Maryland corporation, is a publicly traded, self-managed, Dallas-based real estate investment trust focused on owning quality, well-managed commercial office properties in dynamic markets throughout the U.S. TIER's vision is to be the premier owner and operator of best-in-class office properties in TIER1 submarkets, which are primarily higher density and amenity-rich locations within select, high-growth metropolitan areas that offer a walkable experience to various amenities.

        TIER's most significant asset is its indirect ownership interest in Tier Operating Partnership LP, which, together with its subsidiaries, conducts substantially all of TIER's business, holds substantially all of TIER's consolidated assets and generates substantially all of TIER's revenues.

        TIER was incorporated in the state of Maryland in 2002, and Tier Operating Partnership LP was formed in the state of Texas in 2002 ("Tier OP"). TIER's principal executive offices are located at 5950 Sherry Lane, Suite 700, Dallas, Texas 75225, and its telephone number is (972) 483-2400.

        TIER common stock is listed on the NYSE, trading under the symbol "TIER."

        Additional information about TIER and its subsidiaries is included in documents incorporated by reference into this joint proxy statement/prospectus and "Where You Can Find More Information."

Risk Factors (See page 24)

        Before voting at the Cousins special meeting or the TIER special meeting, you should carefully consider all of the information contained in or incorporated by reference into this joint proxy statement/prospectus, as well as the specific factors under the heading "Risk Factors" beginning on page 24, including the risks that:

•

the Merger is subject to a number of conditions and may not be completed on the terms or timeline currently contemplated, or at all;



•

the exchange ratio is fixed and will not be adjusted in the event of any change in the stock prices of either Cousins or TIER;



•

Cousins and TIER may be unable to successfully integrate their businesses in order to realize the anticipated benefits of the Merger;



•

Cousins and TIER stockholders will be diluted by the Merger; and



•

Cousins may incur adverse tax consequences if Cousins or TIER has failed or fails to qualify as a REIT for U.S. federal income tax purposes.

The Merger

The Merger Agreement (See page 90)

        Cousins and TIER have entered into the Merger Agreement attached as Annex A to this joint proxy statement/prospectus. The Cousins board of directors and the TIER board of directors have both unanimously approved the combination of Cousins and TIER. Cousins and TIER encourage you to read the entire Merger Agreement carefully because it is the principal legal document governing the Merger.

Form of the Merger (See page 90)

        Pursuant to the Merger Agreement, TIER will merge with and into Merger Sub, with Merger Sub continuing its existence as a wholly owned subsidiary of Cousins.

        We expect that the legacy stockholders of Cousins and the legacy common stockholders of TIER will own approximately 72% and 28%, respectively, of the outstanding shares of Cousins common stock.

Merger Consideration (See page 90)

        Under the terms of the Merger Agreement, upon consummation of the Merger, holders of TIER common stock will have the right to receive 2.98 newly issued shares of Cousins common stock for each share of TIER common stock they own immediately prior to the effective time of the Merger, subject to customary anti-dilution adjustments and with cash paid in lieu of fractional shares. The exchange ratio in the Merger is fixed and will not be adjusted for changes in the market value of TIER common

stock or Cousins common stock. Because of this, the implied value of the consideration to TIER stockholders in the Merger will fluctuate between now and the completion of the Merger.

        Based on the closing price of Cousins common stock on the NYSE of $9.88 on March 22, 2019, the last trading day before public announcement of the Merger, the exchange ratio represented approximately $29.44 in Cousins common stock for each share of TIER common stock. Based on the closing price of Cousins common stock on the NYSE of $            on            , 2019, the latest practicable date before the date of this joint proxy statement/prospectus, the exchange ratio represented approximately $            in Cousins common stock for each share of TIER common stock. For more information, see "Comparative Stock Prices and Dividends."

        The following table presents trading information for Cousins common stock and TIER common stock on March 22, 2019, the last trading day before public announcement of the Merger, and            , 2019, the latest practicable date before the date of this joint proxy statement/prospectus. Trading information for TIER common stock adjusted by the exchange ratio of 2.98 is also provided for each of these dates.

        The market prices of Cousins common stock and TIER common stock fluctuate. As a result, we urge you to obtain current market quotations of Cousins common stock and TIER common stock.

Treatment of TIER Equity-Based Awards in the Merger (See page 91)

        At the effective time of the Merger, upon the terms and subject to the conditions of the Merger Agreement, outstanding TIER equity awards will be adjusted as follows:

•

Restricted Stock Awards.  Each award of restricted shares of TIER common stock (which we refer to as a "TIER restricted stock award") that is outstanding immediately prior to the effective time of the Merger will vest in full and be treated in the same manner as any other share of TIER common stock.



•

Restricted Stock Unit Awards.  Each award of restricted stock units corresponding to TIER common stock (which we refer to as a "TIER RSU award") that is outstanding immediately prior to the effective time of the Merger will vest to the extent provided in the TIER 2015 Equity Incentive Plan (which we refer to as the "TIER equity plan") (with any performance goals determined to be achieved as set forth in the TIER equity plan and the applicable award agreements) and will be settled in shares of TIER common stock which will be treated in the same manner as any other share of TIER common stock.

Recommendations of the Cousins Board of Directors (See page 50)

        After careful consideration, the Cousins board of directors, on March 24, 2019, unanimously approved the Merger Agreement and the transactions contemplated thereby, including the Merger, and declared the Merger Agreement and such transactions (including the issuance of Cousins common stock as contemplated by the Cousins Issuance Proposal) to be advisable and in the best interest of Cousins and the stockholders of Cousins.

        After careful consideration, the Cousins board of directors, on April 10, 2019, unanimously approved amendments to the Cousins Articles (i) to increase the number of authorized shares of Cousins common stock (as contemplated by the Cousins Authorized Share Count Proposal) and (ii) to

effect a one-for-four reverse stock split of the Cousins common stock (as contemplated by the Cousins Reverse Stock Split Proposal), and declared such transactions to be advisable and in the best interest of Cousins and the stockholders of Cousins.

        The Cousins board of directors unanimously recommends that holders of Cousins common stock vote "FOR" the Cousins Issuance Proposal, "FOR" the Cousins Reverse Stock Split Proposal, "FOR" the Cousins Authorized Share Count Proposal and "FOR" the Cousins Adjournment Proposal.

        For the factors considered by the Cousins board of directors in reaching its decision to approve the Merger Agreement and the recommendations of the Cousins board of directors, see "The Merger—Cousins' Reasons for the Merger; Recommendations of the Cousins Board of Directors."

Recommendations of the TIER Board of Directors (See page 53)

        After careful consideration, the TIER board of directors, on March 24, 2019, unanimously approved the Merger on the terms and subject to the conditions set forth in the Merger Agreement, and declared the Merger Agreement to be advisable and in the best interest of TIER and the stockholders of TIER.

        The TIER board of directors unanimously recommends that the TIER stockholders vote "FOR" the TIER Merger Proposal, "FOR" the TIER Compensation Proposal and "FOR" the TIER Adjournment Proposal.

        For the factors considered by the TIER board of directors in reaching its decision to approve the Merger Agreement and the recommendations of the TIER board of directors, see "The Merger—TIER's Reasons for the Merger; Recommendations of the TIER Board of Directors."

Opinion of Cousins' Financial Advisor (See page 57)

Opinion of Morgan Stanley & Co. LLC

        In connection with the Merger, at the meeting of the Cousins board of directors on March 24, 2019, Cousins' financial advisor, Morgan Stanley & Co. LLC, which we refer to as Morgan Stanley, delivered to the Cousins board of directors its oral opinion, later confirmed by delivery of a written opinion dated March 24, 2019, that, as of that date, and based upon and subject to the various assumptions made, procedures followed, matters considered and qualifications and limitations on the scope of review undertaken by Morgan Stanley as set forth in its written opinion, the exchange ratio pursuant to the Merger Agreement was fair, from a financial point of view, to Cousins.

        The full text of the written opinion of Morgan Stanley, dated as of March 24, 2019, is attached to this joint proxy statement/prospectus as Annex B and is hereby incorporated into this joint proxy statement/prospectus by reference in its entirety. You should read the opinion in its entirety for a discussion of the assumptions made, procedures followed, matters considered and qualifications and limitations on the scope of the review undertaken by Morgan Stanley in rendering its opinion. You should read the entire opinion and the summary of Morgan Stanley's opinion below carefully and in their entirety. This summary of the opinion of Morgan Stanley set forth in this joint proxy statement/prospectus is qualified in its entirety by reference to the full text of the opinion. Morgan Stanley's opinion was directed to the Cousins board of directors, in its capacity as such, addressed only the fairness of the exchange ratio pursuant to the Merger Agreement, from a financial point of view, to Cousins as of the date of the opinion and did not address any other aspects or implications of the Merger. The opinion did not in any manner address the prices at which shares of Cousins common stock will trade following consummation of the Merger or at any time. Morgan Stanley's opinion was not intended to, and does not, constitute a recommendation to any holder of shares of Cousins common stock or TIER common stock as to how to vote at the Cousins special meeting or the TIER special meeting, respectively, to be held in connection with the Merger or whether to take any other

action with respect to the Merger. Morgan Stanley was not required to opine as to, and its Opinion does not in any manner address, the underlying business decision by Cousins to proceed with or effect the transactions contemplated by the Merger Agreement, or the likelihood that the Merger is consummated. Morgan Stanley's opinion did not address the relative merits of the Merger as compared to any other alternative business transaction, or other alternatives, or whether or not such alternatives could be achieved or are available. See "The Merger—Opinion of Cousins' Financial Advisor" and Annex B.

Opinion of TIER's Financial Advisor (See page 67)

Opinion of J.P. Morgan Securities LLC

        Pursuant to an engagement letter, dated March 22, 2019, TIER retained J.P. Morgan (which we refer to as "J.P. Morgan") as its financial advisor in connection with the Merger.

        At the meeting of TIER's board of directors on March, 24, 2019, J.P. Morgan rendered its oral opinion to TIER's board of directors that, as of such date and based upon and subject to the assumptions made, procedures followed, matters considered and limitations on the review undertaken by J.P. Morgan in preparing the opinion, the exchange ratio applicable to the conversion of each outstanding share of TIER common stock into Cousins common stock in the Merger was fair, from a financial point of view, to the holders of TIER common stock. J.P. Morgan confirmed its March 24, 2019, oral opinion by delivering its written opinion, dated March 24, 2019, to TIER's board of directors that, as of such date, the exchange ratio in the Merger was fair, from a financial point of view, to the holders of TIER common stock.

        The full text of the written opinion of J.P. Morgan, dated March 24, 2019, which sets forth the assumptions made, procedures followed, matters considered and limitations on the review undertaken by J.P. Morgan in preparing the opinion, is attached as Annex C to this joint proxy statement/prospectus and is incorporated herein by reference. The summary of the opinion of J.P. Morgan set forth in this joint proxy statement/prospectus is qualified in its entirety by reference to the full text of such opinion. TIER's stockholders are urged to read the opinion in its entirety. J.P. Morgan's opinion was addressed to TIER's board of directors (in its capacity as such) in connection with and for the purposes of its evaluation of the Merger and was directed only to the exchange ratio in the Merger. The opinion does not constitute a recommendation to any TIER stockholder as to how such stockholder should vote with respect to the Merger or any other matter. For a description of the opinion that TIER's board of directors received from J.P. Morgan, see the section entitled "The Merger—Opinion of TIER's Financial Advisor" beginning on page 67.

Interests of Cousins Directors and Executive Officers in the Merger (See page 80)

        In addition to their interests in the Merger as stockholders, the directors and executive officers of Cousins have interests in the Merger that may be different from, or in addition to, those of Cousins stockholders generally. The Cousins board of directors was aware of these interests and considered them, among other matters, in approving the Merger Agreement. These interests generally include the continued employment or service of the executive officers and directors of Cousins following the Merger.

        For more information, see "The Merger—Interests of Cousins Directors and Executive Officers in the Merger."

Interests of TIER Directors and Executive Officers in the Merger (See page 80)

        In addition to their interests in the Merger as stockholders, the directors and executive officers of TIER have interests in the Merger that may be different from, or in addition to, those of TIER

stockholders generally. The TIER board of directors was aware of these interests and considered them, among other matters, in approving the Merger Agreement. These interests include, among others, vesting of TIER restricted stock awards and TIER RSU awards upon the effective time of the Merger and severance benefits payable upon a qualifying termination of employment. In addition, TIER intends to enter into excise tax gross-up agreements with certain executive officers, pursuant to which such executive officers may become entitled to a tax gross-up if it is determined that any Merger-related compensation, payment or distribution to such executive officer would be subject to the excise tax imposed by Section 4999 of the Code, or any such executive officer incurs interests or penalties with respect to such excise tax.

        Pursuant to the Merger Agreement, immediately following the effective time of the Merger, the Cousins board of directors will be expanded from nine to 11 members, the two new members being Mr. Scott W. Fordham, Chief Executive Officer of TIER and a member of the TIER board of directors, and one individual who was an independent member of the TIER board of directors as of March 25, 2019 to be mutually designated by TIER and Cousins.

        For more information, see "The Merger—Interests of TIER Directors and Executive Officers in the Merger."

Directors and Management Following the Merger (See page 85)

        Pursuant to the Merger Agreement, immediately following the effective time of the Merger, the Cousins board of directors will be expanded from nine to 11 members, the two new members being Mr. Scott W. Fordham, Chief Executive Officer of TIER and a member of the TIER board of directors, and one individual who was an independent member of the TIER board of directors as of March 25, 2019 to be mutually designated by TIER and Cousins.

        The current senior leadership team of Cousins is not expected to change as a result of the Merger. Pursuant to the Merger Agreement, at the effective time of the Merger, the senior leadership team of Cousins will include Mr. Lawrence L. Gellerstedt III as Executive Chair, Mr. M. Colin Connolly as President and Chief Executive Officer, Mr. Gregg Adzema as Executive Vice President and Chief Financial Officer, Ms. Pamela Roper as Executive Vice President, General Counsel and Corporate Secretary, Mr. Richard Hickson as Executive Vice President—Operations, Mr. John McColl as Executive Vice President—Development, Ms. Kennedy Hicks as Senior Vice President—Investments and Mr. Jay Harris as Senior Vice President and Chief Accounting Officer. See "The Merger—Directors and Management Following the Merger" for additional information.

Accounting Treatment (See page 87)

        Cousins prepares its financial statements in accordance with accounting principles generally accepted in the United States (which we refer to as "GAAP"). The Merger will be accounted for by using the business combination accounting rules. For more information, see "The Merger—Accounting Treatment."

Regulatory Approvals (See page 88)

        In connection with the issuance of Cousins common stock in the Merger, pursuant to the Merger Agreement, as a condition to the closing of the Merger, Cousins must file a registration statement with the SEC under the Securities Act, of which this joint proxy statement/prospectus forms a part, that is declared effective by the SEC.

Expected Timing of the Merger (See page 88)

        Cousins and TIER are working to complete the Merger in the third quarter of 2019. However, the Merger is subject to various conditions, and it is possible that factors outside the control of both companies could result in the Merger being completed at a later time, or not at all. There may be a substantial amount of time between the respective Cousins and TIER special meetings and the completion of the Merger. Cousins and TIER hope to complete the Merger as soon as reasonably practicable following the satisfaction of all applicable conditions. For more information, see "Risk Factors—Risks Related to the Merger."

Conditions to Completion of the Merger (See page 102)

        As more fully described in this joint proxy statement/prospectus and in the Merger Agreement, the completion of the Merger depends on a number of conditions being satisfied or, where legally permissible, waived. These conditions include:

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receipt of the requisite approvals of Cousins stockholders and TIER stockholders;



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the approval for listing on the NYSE of shares of Cousins common stock to be issued in connection with the Merger;



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the SEC having declared effective the registration statement of which this joint proxy statement/prospectus forms a part, subject to official notice of issuance;



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the absence of an injunction or law prohibiting the Merger;



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the correctness of all representations and warranties made by the parties to the Merger Agreement and performance by the parties of their obligations under the Merger Agreement (subject in most cases to materiality or material adverse effect qualifications), and receipt of an officer's certificate from each party attesting thereto;



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receipt by each of Cousins and TIER of an opinion to the effect that the Merger will qualify as a "reorganization" within the meaning of Section 368(a) of the Code; and



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the receipt by each of Cousins and TIER of an opinion regarding the other party's qualification as a REIT.

        We cannot be certain when, or if, the conditions to the Merger will be satisfied or waived, or that the Merger will be completed.

No Solicitation (See page 103)

        TIER is subject to a customary "no-shop" provision that requires it to refrain from, and to cease discussions or solicitations with respect to, alternative transactions and subjects TIER to certain restrictions in considering and negotiating alternative transactions. If TIER receives a superior proposal (as hereinafter defined), TIER may provide nonpublic information to the proposing party and engage in discussions or negotiations with the party making such a proposal. TIER shall promptly notify Cousins of any proposal for an alternative transaction within 24 hours and provide the other party with a copy of such proposal.

        In response to a superior proposal, the TIER board of directors may change its recommendation with respect to its stockholder vote, and may terminate the Merger Agreement in order to accept such proposal. Prior to effecting such change, TIER must provide Cousins with notice, reasons for such action and four business days of good-faith negotiations to counter such proposal.

Termination of the Merger Agreement (See page 107)

        The Merger Agreement may be terminated prior to the effective time of the Merger, whether before or after the required approvals of the Cousins stockholders and TIER stockholders are obtained:

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by mutual written consent of Cousins and TIER;



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by either Cousins or TIER, if any governmental entity issues a permanent, non-appealable order, decree or ruling enjoining or prohibiting the consummation of the Merger;



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by either Cousins or TIER, if the Merger is not consummated by October 31, 2019;



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by either Cousins or TIER, if there is a breach of the representations or covenants of the other party that would result in the failure of the related closing condition to be satisfied, subject to a cure period;



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by either Cousins or TIER, if the required approvals of either the Cousins stockholders or the TIER stockholders are not obtained;



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by Cousins, if the TIER board of directors changes its recommendation regarding approval of the TIER Merger Proposal;



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by Cousins, upon a material breach of TIER's obligations not to solicit alternative transactions; and



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by TIER, prior to the TIER special meeting, to enter into a "superior proposal" (as hereinafter defined), subject to compliance with certain terms of the Merger Agreement.

Expenses and Termination Fees (See page 107)

        Generally, all fees and expenses incurred in connection with the Merger and the transactions contemplated by the Merger Agreement will be paid by the party incurring those expenses. For more information, see "The Merger—The Merger Agreement—Fees and Expenses." The Merger Agreement further provides that TIER is required to pay Cousins a termination fee equal to $45,450,000 under certain circumstances. For more information, see "The Merger—The Merger Agreement—Termination of the Merger Agreement."

No Appraisal or Dissenters' Rights (See page 89)

        Under Maryland and Georgia law, the holders of TIER common stock and Cousins common stock and Cousins preferred stock, respectively, are not entitled to appraisal rights in connection with the Merger. For more information, see "The Merger—No Appraisal or Dissenters' Rights."

Material U.S. Federal Income Tax Consequences of the Merger (See page 110)

        TIER and Cousins intend for the Merger to qualify as a "reorganization" within the meaning of Section 368(a) of the Code. The obligation of the parties to consummate the Merger is subject to the receipt by Cousins and TIER of the opinions of their respective counsels to the effect that, on the basis of facts, representations and assumptions set forth in such opinions, the Merger will qualify as a "reorganization" within the meaning of Section 368(a) of the Code. Accordingly, on the basis of the opinions described above, a U.S. holder of TIER common stock generally will not recognize any gain or loss upon receipt of shares of Cousins common stock in exchange for TIER common stock in the Merger (other than gain or loss with respect to cash received in lieu of a fractional share of Cousins common stock, if any).

        You should read the discussion under "Material U.S. Federal Income Tax Consequences of the Merger" for a more complete discussion of the U.S. federal income tax considerations relevant to the Merger. The tax consequences of the Merger to you will depend on your particular facts and circumstances. You should consult your tax advisor to determine the particular tax consequences of the Merger to you.

The Cousins Special Meeting (See page 113)

        The Cousins special meeting will be held at            , at            local time, on            , 2019. You may vote at the Cousins special meeting if you owned shares of Cousins common stock or Cousins preferred stock at the close of business on            , 2019, the record date for the Cousins special meeting. On that date, there were            shares of Cousins common stock outstanding and entitled to vote. Each share of Cousins common stock is entitled to cast one vote on all matters that come before the Cousins special meeting. Each share of Cousins preferred stock is entitled to cast one vote only on the Cousins Reverse Stock Split Proposal and the Cousins Authorized Share Count Proposal.

        At the Cousins special meeting, Cousins stockholders will be asked to consider and vote upon:

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the Cousins Issuance Proposal;



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the Cousins Reverse Stock Split Proposal;



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the Cousins Authorized Share Count Proposal; and



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the Cousins Adjournment Proposal.

        Only the approval of the Cousins Issuance Proposal is a condition to the completion of the Merger.

        The Cousins Issuance Proposal requires the affirmative vote of the majority of the votes cast by Cousins common stockholders at the Cousins special meeting, assuming a quorum is present. The Cousins Reverse Stock Split Proposal and the Cousins Authorized Share Count Proposal each require the affirmative vote of the holders of a majority of the outstanding shares of Cousins common stock and Cousins preferred stock, voting together as a single class, assuming a quorum is present. The Cousins Adjournment Proposal requires the affirmative vote of the holders of a majority of the Cousins common stock represented, in person or by proxy, at the Cousins special meeting and entitled to vote on the proposal, whether or not a quorum is present.

        On the record date, approximately            % of the outstanding shares of Cousins common stock and approximately            % of the outstanding shares of Cousins preferred stock were held by Cousins directors and executive officers and their affiliates. Cousins currently expects that the Cousins directors and executive officers will vote their shares in favor of the Cousins Issuance Proposal, the Cousins Reverse Stock Split Proposal, the Cousins Authorized Share Count Proposal and the Cousins Adjournment Proposal, although none has entered into any agreements obligating them to do so.

        The Cousins board of directors unanimously recommends that Cousins stockholders vote "FOR" all of the proposals set forth above. For more information, see "The Cousins Special Meeting."

Material U.S. Federal Income Tax Consequences of the Reverse Stock Split (See page 121)

        The reverse stock split is intended to qualify as a "recapitalization" for U.S. federal income tax purposes. Accordingly, U.S. holders of Cousins common stock generally will not recognize gain or loss for U.S. federal income tax purposes upon the reverse stock split (except with respect to cash, if any, received in lieu of a fractional share of Cousins common stock).

        You should read the discussion under "Cousins Proposals—Cousins Proposal 2: The Cousins Reverse Stock Split Proposal—Material U.S. Federal Income Tax Consequences of the Reverse Stock Split" for a more complete discussion of the U.S. federal income tax considerations relevant to the reverse stock split. The tax consequences of the reverse stock split to you will depend on your particular facts and circumstances. You should consult your tax advisor to determine the particular tax consequences of the reverse stock split to you.

The TIER Special Meeting (See page 128)

        The TIER special meeting will be held at            , at            local time, on            , 2019. You may vote at the TIER special meeting if you owned TIER common stock at the close of business on            , 2019, the record date for the TIER special meeting. On that date, there were            shares of TIER common stock outstanding and entitled to vote. Each share of TIER common stock is entitled to cast one vote on all matters that come before the TIER special meeting.

        At the TIER special meeting, stockholders of TIER will be asked to consider and vote upon:

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the TIER Merger Proposal;



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the TIER Compensation Proposal; and



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the TIER Adjournment Proposal.

        The approval of the TIER Merger Proposal requires the affirmative vote of the holders of TIER common stock entitled to cast a majority of all of the votes entitled to be cast on the Merger. The approval of the TIER Compensation Proposal requires the affirmative vote of the majority of the votes cast by holders of TIER common stock, assuming a quorum is present. The approval of the TIER Adjournment Proposal requires the affirmative vote of the majority of the votes cast by holders of TIER common stock, whether or not a quorum is present.

        On the record date, approximately            % of the outstanding shares of TIER common stock was held by TIER directors and executive officers and their affiliates. TIER currently expects that the directors and executive officers of TIER will vote their shares in favor of the TIER Merger Proposal, the TIER Compensation Proposal and the TIER Adjournment Proposal, although none has entered into any agreements obligating them to do so.

        The TIER board of directors unanimously recommends that TIER stockholders vote "FOR" all of the proposals set forth above. For more information, see "The TIER Special Meeting."

Rights of TIER Stockholders Will Change as a Result of the Merger (See page 149)

        TIER stockholders will have different rights once they become stockholders of Cousins, due to differences between the governing documents of Cousins and TIER. These differences are described in detail under "Comparison of Rights of Cousins Stockholders and TIER Stockholders."

SELECTED HISTORICAL FINANCIAL DATA OF COUSINS

        The following tables set forth selected consolidated financial information for Cousins as of and for each of the five years ended December 31, 2018, 2017, 2016, 2015 and 2014. All references to "fiscal years," unless otherwise noted, refer to the twelve-month fiscal year.

        The selected historical consolidated financial information for Cousins as of December 31, 2018 and 2017 and for the years ended December 31, 2018, 2017 and 2016 was derived from the audited consolidated financial statements and related notes of Cousins contained in Cousins' Annual Report on Form 10-K filed with the SEC on February 6, 2019, which is incorporated by reference into this joint proxy statement/prospectus. The selected historical consolidated financial information as of December 31, 2016, 2015 and 2014, and for the years ended December 31, 2015 and 2014, were derived from Cousins' audited consolidated financial statements not included or incorporated by reference into this joint proxy statement/prospectus.

        The following information should be read together with the consolidated financial statements of Cousins, the notes related thereto and the related reports of management on the financial condition and performance of Cousins, all of which are contained in the reports of Cousins filed with the SEC

and incorporated herein by reference. For more information, see "Where You Can Find More Information."

SELECTED HISTORICAL FINANCIAL DATA OF TIER

        The following tables set forth selected consolidated financial information for TIER as of and for each of the five years ended December 31, 2018, 2017, 2016, 2015 and 2014. All references to "fiscal years," unless otherwise noted, refer to the twelve-month fiscal year.

        The selected consolidated financial information for TIER as of December 31, 2018 and 2017 and for the years ended December 31, 2018, 2017 and 2016 was derived from the consolidated financial statements and related notes of TIER, contained in TIER's Annual Report on Form 10-K filed with the SEC on February 11, 2019, which is incorporated by reference into this joint proxy statement/prospectus. The selected historical consolidated financial information as of December 31, 2016, 2015 and 2014, and for the years ended December 31, 2015 and 2014, were derived from TIER's audited consolidated financial statements not included or incorporated by reference into this joint proxy statement/prospectus. All numbers reflected in the selected consolidated financial information for TIER below are in thousands, except the number of properties and per share amounts.

        The following information should be read together with the consolidated financial statements of TIER, the notes related thereto, and the related reports of management on the financial condition and performance of TIER, all of which are contained in the reports of TIER filed with the SEC and incorporated herein by reference. For more information, see "Where You Can Find More Information."