Resolves to whichever party's caucuses are elected to majorities in the U.S. House of Representatives and Senate in the 2026 midterm elections. A majority in the House is defined as having more than half of the voting Representatives, and a majority in the Senate is defined as having more than half of the Senators, or exactly half and the vice president.

Independents or members of third parties who caucus with another party are considered part of that party for the sake of determining the majority. Following the 2024 election, there are two such independents remaining in the Senate, both of whom caucus with the Democrats. Independents or third party members who do not caucus with either major party will not be considered a part of either party - thus it is in theory possible that neither party could have the majority in one of the chambers. In that case, the market will resolve to "Other" or an option stating that no party has the majority in the chamber if such an option has been added. If an Independent doesn't make clear whether they will caucus with another party, and their choice determines the outcome of this market, it will not be resolved until their decision is made clear.

This market is based on the incoming Congress that is elected on election day, meaning the winners of all House and Senate races plus the Senators whose seats weren't up for reelection and the vice president. If the actual composition of the 120th Congress differs from this (e.g., someone dies between Election Day and the inauguration of the new Congress), that will not affect the result.