The US Capitol is reflected in the Capitol Reflecting Pool in Washington, DC, US, October 27, 2026.

Umit Bektas | Reuters

The stock market is not yet pricing in a Democratic sweep of Congress — despite some polls and most prediction markets pointing that way — so that scenario could weigh on share prices Wednesday, according to investors and analysts.

Republicans managing to keep control could cause a short-term relief rally, they said.

Short-term moves aside, the typical post-midterm pattern in the months ahead is bullish. But some wonder if the market could buck the positive historical trend this time because the S&P 500 is already up so much this year going into the election.

As far as certain stocks to watch, a big Democratic win on Tuesday night — especially in the Texas governor race — could add fuel to an AI stock sell-off on the notion that more data center restrictions would gain momentum nationally.…