By MICHELLE CHAPMAN
AP Business Writer
Shares of Twitter are surging on a report that co-founder Jack Dorsey will step down as the company’s chief executive. Twitter’s stock, which has consistently underperformed the market, jumped more than 10% at the opening bell Monday. CNBC first reported that Dorsey may step down soon, citing anonymous sources. Twitter did not immediately respond to a request for comment from The Associated Press. Dorsey is also the top executive at Square, a financial payments company that he founded, and some big investors have openly questioned whether he can be effective leading both.