Polymarket gives Democrats 92% chance of taking House

Polymarket traders put the implied probability of Democrats taking control of the U.S. House at 92% on Sept. 28, giving the party a commanding advantage in a market whose prices can move continuously as trading changes.

The figure was recorded at 10:17 a.m. Eastern time in a 24/7 Wall St. analysis. The outlet noted that the House-control price had shifted during the hour before publication, underlining that it was a market snapshot rather than a forecast fixed through Election Day.

The Senate market was materially closer. At 14:12 UTC, Polymarket's Democratic Senate-control contract traded at 62.5 cents, against 37.5 cents for the Republican contract. The Democratic contract had risen 12 cents over the preceding month and 35 cents from a year earlier, with about $5.3 million traded in the event.

On Polymarket US, a 60-cent contract is described as a current market estimate of a 60% probability. The platform says those odds are generated by traders backing their views with money rather than by a bookmaker. Its U.S. operation is run by QCX LLC, doing business as Polymarket US, a CFTC-regulated designated contract market.

A separate Polymarket market on the House popular vote offered a more granular view of traders' expected national margin. Democrats winning the House vote by 8% to 10% was the most highly priced of the cited brackets, at 28.5 cents. A 10% to 12% margin traded at 21.5 cents, while a 6% to 8% margin traded at 18 cents.

Those markets answer a different question from House control. The popular-vote contract resolves on the party receiving the most valid votes for U.S. representative nationwide, including all party candidates but excluding delegates and the resident commissioner. Control of the chamber is determined district by district, so a national-vote margin cannot itself forecast which party holds the House.

Other measures cited in recent coverage likewise gave Democrats an advantage in the House contest. An NPR/PBS News/Marist generic-ballot poll reported by Delaware Online on Sept. 23 showed Democrats leading Republicans by 12 points. A RealClear Polling average of more than 13 pollsters put Democrats at 50.4%, compared with 41.8% for Republicans.

The report described House forecasts as generally favoring a Democratic majority, with Senate control substantially more competitive. On Sept. 23, Polymarket put the probability of a Democratic sweep of both chambers at 66%, while Kalshi priced it at 64%.

Covers separately reported that Kalshi traders also put Democrats' House-flip probability at 92%. It cautioned that market odds can change with polling, candidate developments and fundraising data, and do not guarantee an election result. Democrats could win the House through suburban swing districts even without large popular-vote margins in Florida or Texas.

Prediction markets allow participants to buy and sell contracts tied to potential outcomes, commonly priced from 1 to 99 cents. Their use is expanding during the 2026 election season, according to PBS, even as states weigh restrictions and the National Conference of State Legislatures has identified broad statutory bans on election betting in half of U.S. states.

The Brennan Center has warned that such wagers represent traders' opinions rather than validation of facts, and that predictions can be wrong or confuse voters when they diverge from eventual results. The 2026 midterm election is scheduled for Tuesday, Nov. 3.