Wall Street is bracing for the U.S. presidential election in 11 days, and uncertainty is running high. The latest CNBC All-America Economic Survey showed Vice President Kamala Harris and former President Donald Trump locked in a dead heat with less than two weeks to go before the vote. The data also showed Harris with greater support among women, while Trump led with male voters. Pre-election jitters have crept into the market this week. The S & P 500 is down 0.9% week to date, on pace to snap a six-week advance. There may be more turbulence next week as the election draws closer, but history shows all is not lost for the market. CNBC Pro crunched the numbers going back through the last 10 presidential elections, and found that the S & P 500 has seen a median gain of 0.76% the week before the vote. The week of the election itself, the broad market index has seen a median gain of 0.56%. To be sure, stocks have been under pressure the week before the election in the last two cycles given the uncertainty around each contest. In 2020, the S & P 500 dropped 5.6% the week before the election, then rallied 7.3% the week of the vote. In 2016, the benchmark lost nearly 2% the week prior — then popped 3.8% once the dust settled. Bottom line: History shows the week leading up to an election is historically solid. However, the heightened jitters around the last two contests could signal trouble this time around as well. Elsewhere on Wall Street this morning, KeyBanc downgraded Apple to underweight, citing concerns around the company’s iPhone sales. “We think this shows the iPhone SE is not incremental, and could possibly be cannibalistic to iPhone 16 sales,” KeyBanc wrote. “From our view, if iPhone SE is successful, iPhone Units could rise but [average sales prices] could fall, contrary to consensus.”