"You could say the market is discounting that Trump is going to lose," said Daniel Clifton, Strategas Research head of policy research. "Normally, the S&P predicts the presidential election, but that's usually confirmed by the election portfolio."
Sam Stovall, CFRA chief investment strategist, said since World War II, there have been only two instances where the president or his party lost in November, when the market was higher between July 31 and the November election. In 1980, Democrat Jimmy Carter did not win re-election. During his term, 52 American diplomats and citizens were held hostage in the U.S. Embassy in Tehran for more than 400 days, and were released when Republican Ronald Reagan was inaugurated.