An hour before the first polls closed, Polymarket gave Democrats a 73.5 percent chance of winning both chambers, rising to 98.7 percent by 03:00 CET. NBC News called the House and then the Senate. Favorites won eight of nine early-called Senate races, with South Carolina the biggest miss.
An hour before the first polls closed, Polymarket gave Democrats a 73.5 percent chance of winning both chambers in the 2026 midterms. That figure was recorded at 23:00 CET on 3 November and rose to 98.7 percent at 03:00 CET. Along the way, the odds were 88.5 percent at 01:00 and 92.5 percent at 02:00, before the networks called anything. NBC News called the House at 04:08 CET and the Senate at 05:26 CET on Wednesday.
In the nine Senate races with a Polymarket market that had been called by 05:30 CET, the favorite won eight. Those favorites averaged 79 percent, implying about seven expected wins, versus eight actual. The biggest miss was South Carolina, where Darline Graham was priced at 69.5 percent but Annie Andrews won. Darline Graham was appointed after her brother Lindsey Graham died in July.
Polymarket had Adam Hamilton at 64.5 percent in Kansas, a state Trump carried by 16 points in 2024. NBC News calls his win an upset. The Iowa Senate race was a near coin flip on Polymarket, at 50.5 to 49.5 percent for the later winner Josh Turek. At 05:30 CET the market put Peggy Flanagan at about 99 percent in Minnesota while Michele Tafoya led the partial count. Shortly after 06:00, NBC News called the race for Flanagan.
According to Polymarket, volume was about $164 million on the three national markets and about $67 million on 14 Senate markets. Texas alone drew about $21 million on Polymarket. Both Silver's forecast and prediction markets lean Democratic for the 2026 midterms, with some differences between them.
