Guides

    How Midterm Prediction Markets Settle on November 3: AP Calls, Rules and Timing

    House and Senate control markets will not all pay out the moment networks call a race. Here is how Kalshi and Polymarket settlement works on election night.

    By Prediction Markets US Guides DeskWednesday, October 28, 20268 min read
    How Midterm Prediction Markets Settle on November 3: AP Calls, Rules and Timing

    On November 3, all 435 House seats and 35 Senate seats are on the ballot. Prediction markets on who controls each chamber are among the most-watched contracts in the country. They are also easy to misread when the votes start coming in. A market can sit at 99¢ and not pay out yet. Another can pay out hours before a recount ends.

    The gap between "the networks called it" and "the contract settled" comes down to rules. This guide explains who decides the outcome, how settlement timing works on Kalshi and Polymarket, and what to check before election night. It is educational, not financial advice.

    Where the markets stand

    As of October 28, Polymarket's House control market showed Democrats at 92¢ and Republicans at 9¢, with about $24.7 million in volume. Kalshi's own House explainer put Democrats at 91% as of October 21. Republicans currently hold a 218-214 House majority, with one independent who caucuses with Republicans and two vacancies. A party needs 218 seats for a majority (Kalshi, Polymarket).

    The Senate is closer. Republicans hold a 53-47 majority. Because Vice President JD Vance breaks 50-50 ties, Republicans need only 50 seats to keep control and Democrats need 51. That means Democrats need a net gain of four seats, not three. Kalshi traders priced Democratic Senate control at 62% as of October 15, with more than $63 million traded on that market (Kalshi).

    These prices are market-implied probabilities, not forecasts. They move with polls, fundraising and news.

    Live market view — track these prices yourself:

    Who actually decides the winner?

    There are two different questions: who wins each race, and who controls the chamber. Markets settle on the second one, but it is built from the first.

    Most people will follow the first one through the Associated Press. AP says it will count the vote and declare winners in nearly 7,000 races, including 35 Senate contests, 435 House contests and 36 gubernatorial contests (AP). It also reports that 2026 will be the first cycle in a decade in which all the major TV networks rely on AP vote-count data (Deadline).

    But an AP race call is not automatically a market resolution. Exchanges write their own rules, and those rules name their own resolution sources.

    How Polymarket's House market resolves

    Polymarket's House control market states that its resolution sources are official information from relevant state electoral authorities, the United States Congress, and a consensus of credible reporting. Note what is on that list: official state results and Congress itself, with media consensus as a backstop. That wording matters in a close race, where a projection can come before certification (Polymarket market rules).

    The market page also carries a note that trading on polymarket.com is blocked in the United States and directs US users to polymarket.us. If you are in the US, check which venue you are looking at before you read any price or rule set.

    How Kalshi settlement works

    Kalshi's House control market lists one contract per party. Each is a Yes/No contract priced in cents that pays $1 if that party wins the House majority and $0 if it does not (Kalshi).

    On timing, Kalshi's help center says a market settles when the official outcome is confirmed and its markets team finalizes the result. Once settled, winning contracts are paid to your cash balance. It says most markets settle within a few hours after the outcome is known, often within about three hours, but that this can take longer when the exchange is waiting on official data from a source agency (Kalshi Market FAQs).

    Two other lines from that page are worth memorizing before election night:

    • Close time is not determination time. The displayed close time may not equal the time the outcome is determined. Settlement happens once the source agency confirms the result.
    • An open market does not mean your side hasn't won. Kalshi says a market staying open is not an indication that payout criteria have not been met. It may be waiting for official data.

    Every Kalshi market also has a "Timeline and Payout" section showing when it opened, when it closes and when it is expected to pay out (Kalshi help center). Read it before you trade, not after.

    Why a call and a settlement can be hours or days apart

    Control of a chamber is a count. For the House, it takes 218 seats. If the count is 216 to 214 with several close races uncalled, no one has control yet, and neither the networks nor the exchanges will say otherwise.

    That creates three practical situations:

    1. A clean sweep. One party clears the threshold on election night, and a market tied to that outcome can settle within hours under the timing Kalshi describes.
    2. A pending count. Several close races remain uncalled. The market stays open, and the price can drift well away from where the headlines point.
    3. A rules-driven wait. The count is effectively over, but the rules specify a source, such as official state results or the seated Congress, that has not yet confirmed. The market stays open even though the outcome looks obvious.

    None of this is unique to elections. Kalshi's own FAQ says the wait often comes from source agencies publishing finalized data. Elections just make the wait more visible.

    Live market view — Senate control:

    What to check before you trade on election night

    Run through these before the first polls close:

    • Read the exact rules on the market page. Find the resolution source, the determination date and any language about recounts, certification or seating.
    • Know the threshold. House control is 218 seats. Senate control is 50 seats for Republicans because of the vice president's tiebreaking vote and 51 for Democrats.
    • Separate race calls from market settlement. A call is a reporting event. A settlement is a contract event.
    • Expect volatility between the first results and the last. Early returns often come from fast-counting areas and do not represent the whole electorate.
    • Mind the platform and your location. Contracts, availability and rules differ by venue.

    A note on integrity

    Election markets are also under unusual scrutiny. Polymarket's head of global intelligence and investigations told NPR the company has investigated "dozens" of election-related bets and that at least two have been referred to the CFTC, according to a person familiar with the probes. Kalshi announced its own election surveillance system in May that uses FEC data to block listed campaign staffers from trading (NPR). Surveillance does not change how a contract resolves, but it shows both platforms treating election markets as a special risk.

    Frequently asked questions

    Do prediction markets settle as soon as the AP calls the House? Not necessarily. Settlement follows the exchange's own rules and sources. Kalshi says most markets settle within a few hours of the outcome being known, but waiting on official data can take longer. Polymarket's House market names state electoral authorities, Congress and a consensus of credible reporting.

    Why is my market still open if the outcome looks decided? Kalshi says an open market does not mean payout criteria are unmet. It may be waiting for official data from a source agency, or for a determination time written into the rules.

    How many seats does each party need? The House needs 218 for a majority. In the Senate, Republicans need 50 because the vice president breaks ties, while Democrats need 51.

    Where can I follow the count? AP publishes results and race calls on its elections hub (AP). For live market prices, see the House control market and the Senate control market on PredictionMarkets.US.

    Is this financial advice? No. Prediction markets carry risk and prices are not forecasts. Check the rules for any contract before you trade.

    The bottom line

    On election night, the number that matters is not the one on TV. It is the one named in the contract rules. Read the resolution source, know the 218 and 50-or-51 thresholds, and expect the market to move on its own clock. Follow both chambers live on PredictionMarkets.US.

    Sources & Verification

    Back to Articles