shares of exelon corp exc sank 042 to 4308 wednesday on what proved to be an allaround grim trading session for the stock market with the sp 500 index spx falling 041 to 409195 and dow jones industrial average djia falling 011 to 3364650 exelon corp closed 763 short of its 52week high 5071 which the company achieved on april 21st the stock underperformed when compared to some of its competitors wednesday as nextera energy inc nee rose 032 to 7859 duke energy corp duk rose 006 to 9941