How investors are gaming out U.S. election night

From the beach towns of Pinellas, Florida, to the suburbs of Bucks County, Pennsylvania, Wall Street will be closely watching a few dozen counties on Tuesday night for hints on who will win the U.S. presidential race.

Investment firms, faced with the prospect of a chaotic election complicated by an unprecedented number of mail-in ballots, have hired political analysts and crunched voting data to try to identify crucial counties and Senate races that might tell them which way the vote is headed.