Wall Street eyes divided Congress as most likely midterm outcome

The midterm elections are still weeks away, but Wall Street has already picked its preferred winner: nobody. Major financial institutions including Morgan Stanley, JPMorgan, and UBS are coalescing around the same base case for November 3: Democrats flip the House while Republicans hold the Senate. Prediction markets currently assign a 44% to 50% probability to Democrats regaining the House, while full Republican retention of both chambers sits at a comparatively slim 10% to 16%.

The math behind the gridlock trade

Republicans hold the House by a razor-thin margin, roughly 218 seats to Democrats’ 214. The Senate tells a different story. Republicans sit on a 53-47 majority, a buffer wide enough to survive the typical midterm headwinds. About 47% of fund managers surveyed by Bank of America expect exactly this scenario heading into the vote.

Why markets love a Congress that can’t agree on lunch

The S&P 500 has averaged roughly 5.7% returns in the three months following recent midterm elections. This dynamic sets up what strategists are calling a potential post-election relief rally, with capital flowing back into equities pushing prices higher into early 2027.

The tail risk that keeps strategists up at night

Morgan Stanley’s Michael Hartnett has flagged a full Democratic sweep of both chambers as the tail risk worth watching. If Democrats manage to win both the House and Senate, Hartnett’s team sees equity declines potentially exceeding 10%.

A Democratic sweep could put downward pressure on the US dollar and bond yields. It could also introduce new regulatory scrutiny over the AI investment boom. Defense stocks appear well-positioned under almost any configuration, enjoying bipartisan support, while financial companies and certain technology firms face potential regulatory tightening under a Democratic-controlled Congress.