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 $21.8M 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 two leading combinations barely moved through the back half of August even as another $2M crossed the board. 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 $21.8M 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. As of August 31, 2026, the two lines sharing a Democratic House add to 86.5%, within half a point of the 87c the standalone U.S. House control odds carry, and the two lines sharing a Democratic Senate add to exactly 50%, matching the Democratic contract on the standalone U.S. Senate control odds. That is the signature of a board being priced coherently rather than in isolation.
That decomposition is also what has changed since early summer, and what has stopped changing since. The House marginal hardened into a heavy favorite while the Senate marginal settled onto a literal coin flip, and through the back half of August both held. The distance between the top two lines is the price of the Senate, not the price of the House.
The Senate is the only chamber still carrying real uncertainty on this board, and it gets built one race at a time. Republicans enter the cycle holding a 53-47 majority, so Democrats need a net gain of four seats to reach 51 and control the floor outright.
Two contests at opposite ends of the map show how that gets priced. In Maine, the Maine Senate 2026 odds put the Democratic contract at 70c on a $5.7M board as of August 31, 2026, treating a Republican-held seat as more likely than not to flip. In Texas, an $11.1M board has James Talarico at 51c against 50c for the Republican side, with Kalshi and Polymarket inside two cents of each other. A Texas Senate seat trading as a coin flip is the clearest single explanation for why the national Senate marginal on this board sits where it does.
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 has led the board outright since it separated from the split line in early summer, and it held the top spot through August. 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 86.5% of the board as of August 31, 2026, 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 drifted lower through July and has traded in the mid-teens across August, 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 at a single cent on both books, 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 August 31, 2026, a Democratic sweep of both chambers leads the board at 49c, the split Congress of a Democratic House and a Republican Senate is second at 37.5c, and a Republican sweep is third at 15c. The board prices four Senate-by-House combinations plus Other across Kalshi and Polymarket on roughly $21.8M 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, which ran to four cents on the leading line on August 31, 2026, flags where traders disagree on the paired result.
The Senate. As of August 31, 2026, adding the two lines that share a Democratic House implies an 86.5% chance Democrats take the House, within half a point of the standalone House control market at 87c, while the two Democratic-Senate lines add to exactly 50%. The gap between the top two combinations is the price of the Senate.
Watch the Senate seats carrying the most volume. Texas trades near a coin flip and the Maine Democratic contract sits at 70c, and those two alone explain much of the national Senate marginal. Generic ballot polling and presidential approval move the whole board, and a redistricting ruling that reopens the House math is the single event that would revive the Republican sweep line.