One year ago, Republicans’ chances of retaining the Senate after the 2026 midterms were over 80%. But today, control of the Senate is shaping up to be one of the most competitive contests of the election cycle.
Traders now give Democrats a 51% chance of winning the upper chamber, compared with 49% for Republicans, making the race essentially a toss-up heading into November.
While the Senate race looks extremely competitive, traders currently see a more lopsided contest in the House of Representatives.
In the 2026 House control market, Democrats are strong favorites to win the chamber. At the moment, traders give Democrats an 84% chance of controlling the House after November, compared with 15% for Republicans.
For traders interested in the overall structure of Congress rather than individual chambers, another market combines these outcomes. The Congress balance of power combo market allows participants to forecast which party will control the House and Senate after the 2026 elections.
Current pricing suggests the most likely outcome is Democrats controlling both the House and the Senate, which traders assign a 50% probability. The next most likely scenario is Democrats winning the House while Republicans retain the Senate, currently priced at 37%.
Markets assign much lower probabilities to the remaining outcomes. Republicans controlling both chambers is priced at 14%, while Republicans winning the House but Democrats capturing the Senate is priced at just 1%.
These probabilities reflect how traders combine expectations from the individual chamber markets. Because Democrats are currently strong favorites in the House market but only slightly ahead in the Senate market, the combined scenarios tend to revolve around those two outcomes.
The takeaway:
For now, the message from prediction markets is clear. The race for the Senate has tightened dramatically, with Democrats now holding a narrow 51% to 49% edge in the control market.
At the same time, traders currently see Democrats as strong favorites to win the House, and the balance of power market suggests the most likely overall outcome is Democratic control of both chambers.
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