The election outcome that will make stocks plunge is not a Trump win

Stocks will rally after Tuesday's election regardless of whether Hillary Clinton or Donald Trump wins, according to Fundstrat's Tom Lee.

But the one scenario that would tank stocks is if Trump loses and refuses to accept defeat, he said in a note on Monday. Lee said the S&P 500 could fall 5% by the year's end if that happens.

He assigned a 3% probability to post-election pushback by Trump, and a 0% chance to Clinton.

Stock-market trading over the past two weeks reflects that Clinton may be Wall Street's preferred candidate.

Since the FBI said on October 28 that it was going through additional emails linked to her private server, a move that may have improved Trump's chances in the election, investors hedged their portfolios, and some sold stocks so they'd be able to profit if the market falls. Then on Monday, stocks jumped after the FBI's Sunday announcement that it again found no reason to charge her even after looking at the new emails.

Randy Frederick, managing director of trading and derivatives at Charles Schwab, said there was a spike in options-market activity right after FBI Director James Comey's first letter to Congress on October 28 as investors hedged.

"Most people are prepared for a surprise," he told Business Insider on Friday.

"They're not expecting it, but I always say that as long as the odds of something happening are greater than zero, that means it could happen."

Trump's refusal to concede would is not unimaginable. Trump has repeatedly said the general election is rigged against him.

During the final presidential debate, Trump refused to promise he would accept the results, and said he would look at them when they're released. The following day, he said he would accept the results if he won.

Here's Lee's breakdown of all the election scenarios and how they could impact the stock market: