Wall St. ends flat amid election doubts, M&A flurry

Wall Street ended barely changed on Monday as investors digested the latest large-scale corporate mergers as well as the most recent twist in a tumultuous U.S. presidential election. Stocks were jolted Friday by disclosure that the FBI was investigating more emails as part of a probe into Hillary Clinton's use of a private email system, injecting fresh uncertainty over the Democratic candidate's presumed lead in the presidential election over Republican rival Donald Trump. Opinion polls have sho