U.S. stocks waffled between small gains and losses Wednesday as shares of consumer-staples and energy companies slumped and the S&P 500 hovered just below its all-time high. U.S. crude for September delivery settled down $2.23, or 3.2%, at $66.94 a barrel after data showed total U.S. stockpiles of oil and fuel hit a seven-month high, suggesting supply was outpacing demand.