U.S. markets and stock ETFs pulled back on risk-off selling as investors fled relatively riskier equities for safer fixed-income assets. On Wednesday, the Invesco QQQ Trust (NASDAQ: QQQ) was flat, SPDR Dow Jones Industrial Average ETF (NYSEArca: DIA) fell 0.5% and SPDR S&P 500 ETF (NYSEArca:...