Congress Balance of Power 2026 is the combined-control market: one contract on which party holds the Senate and the House together after the November 3, 2026 midterms. It prices all four Senate-by-House combinations plus an Other outcome, so a split Congress is its own line instead of a catch-all. Roughly $19.8M in cumulative volume trades across Kalshi and Polymarket, and the two chambers are no longer equally live: the House side of the board has consolidated hard behind one party, leaving the Senate as the variable that separates the top lines. The live board above ranks the current cross-platform price on each of the five paths.
Congress Balance of Power 2026 is the single market that prices the whole legislature at once. Instead of trading the House and the Senate separately, it asks one question: which two-chamber outcome lands after the November 3, 2026 midterms? The board prices every combination the two races can produce, all four Senate-by-House pairings plus an Other line, which is why it reads as a five-outcome market rather than a simple three-way call. Roughly $19.8M in cumulative volume now trades across Kalshi and Polymarket, up from $15.9M at the start of July, making it one of the most-traded down-ballot markets of the cycle. The live board above ranks the current price on each path.
The combined-control market sits one level above the two chamber markets it summarizes. The House puts all 435 seats on the ballot every two years, and 218 is the number that decides the majority. The Senate stages roughly a third of its 100 seats each cycle, with 51 seats, or 50 plus the vice president, controlling the floor. Congress Balance of Power 2026 takes the result of both races and resolves to one of five combined lines.
The useful property of a combined board is that it decomposes. Add the two lines that share a House outcome and you get the market's implied probability for the House on its own. Add the two that share a Senate outcome and you get the Senate. Run that arithmetic and the numbers land within a cent or two of the standalone U.S. House control odds and U.S. Senate control odds, which is the sign of a board being priced coherently rather than in isolation.
That decomposition is also what has changed since early summer. The House marginal has hardened into a heavy favorite while the Senate marginal still sits close to a coin flip, so the combined board is now effectively a Senate market wearing a two-chamber label. The distance between the top two lines is the price of the Senate, not the price of the House, and individual seat contests such as the Maine Senate 2026 odds are where that Senate probability gets built one race at a time.
Five lines split the entire board, one for each way the two chambers can break plus a residual.
Democratic House, Democratic Senate: a Democratic sweep of both chambers and unified control of the legislative branch. This line now leads the board outright after trading level with the split line through early summer, and what it really prices is the Senate conditional on a Democratic House.
Democratic House, Republican Senate: the split Congress, Democrats taking the House while Republicans hold the Senate. It was the co-leader in July and is now the clear second line. Together these two outcomes carry the overwhelming majority of the board's probability, which is another way of saying the House has been priced close to settled.
Republican House, Republican Senate: a Republican sweep, the mirror of the Democratic unified line. It has drifted lower since July, and its price tracks the party's ability to defend both majorities against the midterm headwind that historically works against the party holding the White House.
Republican House, Democratic Senate: the reverse split, Republicans holding the House while Democrats take the Senate. It is the least likely of the four combinations and trades in low single digits, because it requires the chamber the market treats as decided to flip and the chamber it treats as open to break the other way.
Other: any result falling outside those four cleanly defined pairings. Because the four combinations already cover every ordinary Senate-and-House outcome, the Other line sits at the bottom of the board and functions as a settlement backstop rather than a real contender.
The market is determined by the November 3, 2026 midterm results and settles once control of both chambers is established. Each chamber goes to the party winning a majority of voting seats, with the vice president's tiebreak counting for a 50-seat Senate, and with the first elected Speaker and the first selected President Pro Tempore of the 120th Congress serving as the fallback if the seat math stays ambiguous. Seats decided by a runoff are attributed by the runoff result even when that vote happens after November. Members elected as independents count toward the party they caucus with, and if those decisions stay undeclared the contracts can remain open until January 4, 2027 at 11:59 PM ET. The contracts carry a listed expiration of April 3, 2027 as an outer backstop.
The combined board is best read next to its two components, the House control market and the Senate control market, which price each chamber on its own while this one prices every pairing of the two together. Because the Senate is the chamber still moving the board, individual contests such as the Texas Senate 2026 odds and the Maine Senate race odds are worth watching seat by seat. For the wider slate of election, approval, and policy contracts, browse the politics prediction markets or the full prediction market board.
Congress Balance of Power 2026 is determined by the results of the November 3, 2026 midterm elections and settles once control of both chambers is established. Each of the four combination contracts pays out only if its exact Senate-and-House pairing occurs, and the Other contract pays out if the result falls outside those four pairings. A party controls a chamber by winning a majority of its voting seats; a 50-seat Senate goes to the party holding the vice presidency, and if the math remains ambiguous the chamber is attributed to the party of the first elected Speaker or the first selected President Pro Tempore of the 120th Congress. Seats decided by a runoff are attributed by the runoff result even if that vote occurs after November 2026, seats not on the ballot are attributed to the party holding them on election day, and members elected as independents count toward the party they caucus with. If independent caucus decisions stay undeclared, the market can remain open until January 4, 2027 at 11:59 PM ET, and the contracts carry a listed expiration of April 3, 2027 as an outer backstop. Resolution sources are official state electoral authorities, the United States Congress, and a consensus of credible reporting.
As of mid-August 2026, a Democratic sweep of both chambers leads the board near 48c, the split Congress of a Democratic House and a Republican Senate is second near 38c, and a Republican sweep is third near 14c. The board prices four Senate-by-House combinations plus Other across Kalshi and Polymarket on roughly $19.8M in cumulative volume.
It is determined by the November 3, 2026 midterm results and settles once control of both chambers is established. Runoffs count even when held after November, undeclared independent caucus decisions can hold it open until January 4, 2027 at 11:59 PM ET, and the contracts carry a listed expiration of April 3, 2027 as an outer backstop.
The combined-control question trades on both Kalshi and Polymarket, the two platforms aggregated on the board above. Comparing them is useful because the spread between the two on the same combination, currently a cent or two on the leading lines, flags where traders disagree on the paired result.
The Senate. Adding the two lines that share a Democratic House implies roughly an 87% chance Democrats take the House, matching the standalone House control market, while the two Democratic-Senate lines add to about a coin flip. The gap between the top two combinations is effectively the price of the Senate.
Watch the roughly 33 to 34 Senate seats on the 2026 ballot, since that chamber alone now separates the two leading lines, plus generic ballot polling and presidential approval. Any redistricting ruling that reopens the House math is the single event that would revive the Republican sweep line.