Wall Street is bracing for the possibility of a Donald Trump victory come Tuesday, and if it happens, things might get ugly.

The FBI's decision to reinvigorate its investigation into Hillary Clinton's emails injected new levels of uncertainty into Election 2016, and what seemed like near-certain victory for Clinton just days ago now appears to be almost a toss-up. A RealClearPolitics average of polls gives Clinton just a 1.6-point lead over her Republican rival in a two-way matchup, and Nate Silver's FiveThirtyEight has Clinton's odds, while still greater than Trump's, at their lowest levels in weeks.

In other words, the presidential race is tightening, and the markets don't like it. The benchmark Standard & Poor's 500 Index fell for a ninth straight day, the longest losing streak since 1980, and ended the week down about 1.9%. The Nasdaq fell 2.8% as uncertainty surrounding the U.S. election outcome surged.

The prospect of a Trump win appears to be what really has investors on edge, and with good reason. A perceived increased probability of a Clinton victory has spurred positive swings in the markets this election cycle, and conversely, an increased probability of a Trump victory has caused selloffs.

Markets dropped last week Friday following news of FBI director James Comey's letter to Congress.

Stocks fell around 0.7%, the Mexico peso declined 1.8%, and the VIX futures market, which measures market volatility, climbed about 0.5 points. The Canadian dollar, the South African rand and the South Korean won fell, as did oil. After the initial shock and as it became clearer the FBI had no smoking gun, the markets bounced back tepidly, undoing about a third to half of their initial reaction.

Trump's presidency would cut the value of benchmark indexes in the U.S., the U.K. and Asia by 10% to 15%, slash the price of oil by $4 a barrel and prompt a 25% decline in the Mexican peso, according to one Brookings Institution study.

There are ways to make money if Trump becomes POTUS No. 45.

The price of gold surpassed $1,300 this week as investors sought out safe havens in this week's turmoil. According to one HSBC analyst, it could jump to $1,500 under a President Trump. And for investors looking to live a little, there's always Bitcoin.

TheStreet has put together a portfolio of 15 stocks that could do well with Trump in the White House. The list includes Mexican cement company Cemex (CX) - Get Report , which could help build his border wall, and Capital One Financial (COF) - Get Report , which would score a win if he is successful in dismantling Dodd-Frank.

TheStreet has a list of Clinton-friendly stocks, too. Among them are HCA Holdings (HCA) - Get Report and Aetna (AET) , which would benefit from her promised Affordable Care Act improvements. The SPDR S&P 500 ETF Trust (SPY) - Get Report is in there as well -- logical, given the markets' apparent preference for her presidency and the stability it would offer.

Clinton, Trump and their surrogates will be hitting the campaign trail hard this weekend.

Vice President Joe Biden will head to Pennsylvania, Senator Bernie Sanders to Colorado and Arizona and President Obama Florida. The Trump kids will be in Florida, North Carolina, New Hampshire and Pennsylvania, and surrogates like Governor Sarah Palin and Senator Jeff Sessions are set to campaign as well. The candidates themselves, of course, will be out, too.

With Election Day just three days away, Wall Street and all Americans are on edge. Whoever you're voting for, you can probably agree on one thing: we're all ready for this to be over. Except for Donald Trump if he loses.