U.S. stocks closed mostly lower Wednesday, extending losses for a third straight session as investors weighed a mixed retail sales last month. Wednesday’s declines were led by the utility sector, with electrical power company AES Corp. (NYSE:AES) dropping nearly 3 percent after its earnings results missed Wall Street estimates earlier this week.

Notable companies reporting after the closing bell Wednesday include department store J.C. Penney Corp., burger joint Shake Shack Inc. and network equipment maker Cisco Systems Inc.

The Dow Jones Industrial Average (INDEXDJX:.DJI) lost 7.54 points, or 0.04 percent, to close at 18,061. The Standard & Poor’s 500 index (INDEXNASDAQ:.IXIC) dipped 0.65 points, or 0.03 percent, to end at 2,098. However, the Nasdaq composite (INDEXSP:.INX) added 5.50 points, or 0.11 percent, to finish at 4,982.

Market professionals are looking ahead to Thursday’s economic calendar, which includes weekly jobless claims, or the number of Americans filing new claims for unemployment, due out at 8:30 a.m. EDT. Initial claims for state unemployment benefits remained near a 15-year low as claims rose 3,000 to a seasonally adjusted 265,000 for the week ended May 2, the Labor Department said last week.

Economists expect last week's jobless claims to rise 10,000 to 275,000, according to analysts polled by Thomson Reuters.

Chemical maker DuPont Co. (NYSE:DD) led the Dow lower Wednesday, dropping more than 6 percent to close at $69.33. The company’s board won a proxy fight against hedge fund Trian Fund Management, led by Nelson Peltz. Trian, which is DuPont's fifth-largest shareholder, had been seeking four seats on the board.

The technology sector was the largest gainer Wednesday, with Chipmaker Intel Corporation (NASDAQ:INTC) the biggest gainer in the blue-chip index, adding 1.2 percent. 

Meanwhile, shares of Southwest Airlines Co. (NYSE:LUV) dipped 2 percent Wednesday after the company announced it plans to raise its quarterly dividend to 7.5 cents per share, up from a previous dividend of 6 cents per share. The board also authorized a new billion-dollar share buyback program, as the airliner plans to repurchase $1.5 billion of the company's stock.