What an election contract actually settles on

An election event contract looks like the simplest instrument a venue lists. The title names a race and a party, and everybody knows when election night is. Neither of those things decides it. What decides it is a sentence in the market's rules that names one event — a call by a set of news organisations, a count certified by a state, a senator sworn in, the party of a Speaker on a particular morning — and a party who is allowed to say that event has happened.

The four venues in this catalogue that list contracts on the 3 November 2026 midterms name different events, use different deciders and pay on different timetables, for contracts whose titles read almost the same. This page is built from the documents that settle them: Kalshi's filed contract terms and the rules its public API serves, the resolution text of Polymarket's markets and its UMA documentation, Polymarket US's rulebook and its filed election terms, and the rules printed on PredictIt's market pages.

How it works

The chain from a ballot to a payout has five links, and the market title describes none of them.

1. The question the rules actually ask. Five different questions hide behind headlines that read alike: who won a race as projected by news organisations, who won it as certified by the state, who was seated, which party controls a chamber, and by how many seats or votes.
2. The event that answers it. A decision-desk projection, a certified result, a certificate of election presented to the Senate, a Speaker elected by the House, or a total published by the Clerk of the House.
3. The named source. A list of outlets, a state electoral authority, congress.gov — or, in one venue's case, no named source at all.
4. The party that decides. The exchange itself on Kalshi, Polymarket US and PredictIt; a bonded proposal under UMA's optimistic oracle on Polymarket's international platform.
5. The timetable. When trading stops, when the contract expires, and how long settlement may wait — for a recount, a runoff, an independent's caucus decision or a new Congress.

One headline, five questions

Take the question every venue lists: which party wins the House.

• On Kalshi it is a question about the Speaker. The filed CONTROL terms say the payout criterion is met where "the leader of <chamber of Congress> is a member of <party> on the Expiration Date", and that for the House "this is the Speaker of the House". The expiration date is 1 February of the year the new term begins, at 10:00 AM ET, and the source agency is congress.gov. Seats are never counted, unless the news organisations settle it first (below).
• On Polymarket it is a question about seats. The market's rules say a party wins control "if it wins a majority of the chamber's voting seats", attribute each seat "to the party under which the member was elected", count runoffs, and count an independent who formally caucuses, or announces an intent to caucus, with a party. Only if nobody has a majority does the first elected Speaker decide.
• On Polymarket US it is the same seat question, worded the same way, on its "U.S House Midterm Winner" contract, with the outcome "sourced from relevant state electoral authorities, and the United States House of Representatives".
• On PredictIt it is a question about districts, with a different fallback: the contract that resolves Yes is the party "whose candidates are elected in a majority of districts", and "in the event that no party wins a majority of seats, all contracts shall resolve to No."

A single Senate race splits the same way. Kalshi's SENATEPARTY terms pay on the party of "the first candidate who presents a certificate of election" for the seat and "who is sworn into the U.S. Senate"; if the winner changes party between the election and the oath, the market "will resolve based on the party they were a part of on election day". Polymarket's Georgia market names three news organisations. PredictIt's Georgia market names none. And a margin contract is a different question again: Polymarket US's House popular-vote margin contract is computed from "the certified results from the United States Clerk of the House", not from any count published on election night.

Four venues, four deciders

Kalshi decides, as the exchange, and lets the newsrooms move the date. The CONTROL and SENATEPARTY terms both carry the same accelerated-resolution clause: the contract "may be resolved on an accelerated basis if (A) at least four (4) of the eight (8) Designated Media Sources have declared a winning candidate, party, or option, and (B) none of the Designated Media Sources have issued a contradictory declaration." The eight are The New York Times, the Associated Press, Decision Desk HQ, CNN, Fox News, NBC News, CBS News and ABC News. A declaration is "a formal projection of victory by its centralized decision desk" or "an unambiguous statement in a news article"; a network and all its local affiliates count as one source, and the national desk overrides an affiliate. The live House market in Kalshi's public API states the result in one line: it "may be determined early based on a consensus of media calls projecting control of the U.S. House", and otherwise "victory will be determined by the party identification of the Speaker of the House on February 1, 2027." The series names its settlement source as the Library of Congress, at congress.gov.

Before settlement Kalshi may open its Market Outcome Review Process at its sole discretion, and under Rule 7.2 it may designate a new source agency and underlying if something threatens the reliability of the one named. There is no bond, no dispute window and no vote.

Polymarket's international platform decides nothing. An outcome is proposed to UMA's optimistic oracle against a bond, stays pending through a challenge period during which anyone can dispute it, and a dispute goes to UMA's Data Verification Mechanism, where stakers commit votes over 24 hours and reveal them over the next 24. Polymarket's own resolution page gives the challenge period as two hours, an undisputed resolution as about two hours after the proposal, and a disputed one as four to six days in total. The mechanism in full is on who decides the outcome and in the optimistic oracle entry.

What a proposer and a voter read is the market's text, and Polymarket's election texts come in two kinds. The House and Senate control markets name "official information from relevant state electoral authorities, the United States Congress, and a consensus of credible reporting" — three sources, no ranking between them, and no number of outlets that makes a consensus. The state Senate races name three outlets and a fallback: "The resolution source for this market is the Associated Press, Fox News, and NBC. This market will resolve once all three sources call the race for the same candidate. If all three sources haven't called the race in this state for the same candidate, this market will resolve based on the official certification." Those markets are "inclusive of any run-offs", so a race that goes to a runoff is not over on election night.

Polymarket US decides, as the exchange, from official results first. Its rulebook dated 30 September 2026 makes the exchange the Source Agency. The clearest statement of how it treats an election is the First Round Election Winner terms for Senate races, self-certified to the CFTC on 22 September 2026: the primary source is "the official electoral authority responsible for certifying the results", followed by a secondary list of twenty-five outlets from Reuters and the Associated Press to NPR, CNN and Fox News. Settlement may be accelerated on "the consensus of Secondary Sources that have made declarations determinative of a given outcome", where a declaration is a formal projection by a centralised decision desk or an unambiguous statement, and "statements indicating that an outcome is 'leading,' 'on track,' 'likely,' or similar conditional language will not qualify." Polymarket US's own documentation adds that political markets "may take longer if certification or official publication is required." Under Rule 10.4 named officers may review a contract before settlement, and "Determinations made by the Company are final."

PredictIt decides under rules that name no source. Both its House and its Georgia Senate market close on the same reservation: PredictIt "reserves the right to wait for further official, party, judicial or other relevant announcements, reports or decisions to resolve any ambiguity or uncertainty before the market is settled", markets "may stay open or incur a delay in settlement well past the date of the contest", and its decisions "shall be at PredictIt's sole discretion and shall be final." Its own trading guide, as the venue card records, says the headline question only approximates the Rules and that the Rules decide.

From election night to a payout

A projection and a certification are different events, published by different people. A projection comes from a news organisation's decision desk on election night or the days after. A certification comes from each state's electoral authority, on that state's own timetable, after canvassing and any recount. A contract that names calls can settle within hours of the last qualifying call; one that names official results waits for the slowest certification it depends on; one that names the Speaker waits for the new Congress to elect one.

Recounts and contests hold a contract open; they do not void it. Polymarket US's filed terms are the most explicit: where voting has concluded but results "have not been certified by the Sources by Expiration, whether because certification is delayed, withheld, or subject to formal contest, challenge, annulment, recount, or other proceedings", the contract "will remain open until the Underlying is finally determined", and the expiration date there is the earlier of the official declaration and two years after the election. Kalshi's Senate-seat terms run to the first 10:00 AM ET after the swearing-in or a year after the vote, whichever is sooner. PredictIt reserves the right to wait for a judicial decision.

Independents can hold a control market into January. Polymarket and Polymarket US both say that if the caucus decisions of members elected as independents cannot be determined on the date of the election, the market "may remain open until the earlier of" an announcement of their intent "or (ii) January 4th, 11:59 PM ET of the following calendar year", after which an undeclared member counts for nobody.

A market that stops trading has not necessarily paid. On Kalshi the last trading time is the expiration time, and settlement is "no later than the day after the Expiration Date, unless the Market Outcome is under review"; the live House market carries a close time of 10:00 AM ET on 1 February 2027 and is flagged as able to close early. On Polymarket trading stops when the market resolves, so the price keeps moving through the challenge period and any dispute. On Polymarket US the last trading time equals expiration unless the Contract Outcome Review Process is opened, and a review moves settlement to the day the review concludes. The end dates its public gateway carries for the midterm contracts run to 15 January 2027 for the seat-count and popular-vote contracts and to the night of 1 February 2027 for the House winner — and the first-round Senate terms say the exchange may move expiration when data are delayed.

What happens after expiration does not count. Kalshi's terms say revisions to the underlying "made after Expiration will not be accounted for". Polymarket US's say adjustments to official results count "only if reported by Expiration", and that results annulled by a court after expiration do not affect settlement. A recount that finishes after a contract has paid changes the record, not the payout.

When the question turns out to be ambiguous

The rules above already answer most of the cases that make election contracts ambiguous, and they answer them differently.

• No majority. Kalshi: the Speaker's party, which is its test anyway. Polymarket and Polymarket US: the first elected Speaker's party for the House; for the Senate, the party with half the seats and the Vice Presidency, then the first President pro tempore. PredictIt: every contract resolves No.
• A member-elect switches party or leaves. Polymarket and Polymarket US attribute the seat to the party under which the member was elected. Kalshi's Senate-seat contract uses the party on election day, and if the seat falls vacant before seating, the party of whoever is first sworn in to it.
• A nominee is replaced before election day. Polymarket's Senate markets follow the party: "the market will resolve based on the replacement nominee of the party."
• A named person can no longer win. Polymarket US Rule 10.5 settles a contract whose primary subject dies or is incapacitated at last traded prices from before the event became known, and says those determinations are "final and not subject to review."
• The election is postponed or cancelled. Polymarket US's filed terms keep the contract open for a rescheduled election, and otherwise allow settlement "at last fair market prices" or a review.
• Nobody can tell. On Polymarket a dispute can end in "Too Early", which rejects the proposal because the event has not concluded, or "Unknown/50-50", where each token redeems for $0.50. Polymarket can also post an "Additional context" clarification on chain that voters are told to consider; it may not change the question's intent. On the three exchanges the answer is the exchange's review, and on PredictIt "the fairest and most appropriate course of action" as PredictIt sees it.

A fallback at a fair price, at last traded prices or at fifty cents is not the dollar a reader expected to collect; it is the branch to read before the position, not after.

The legal background, stated narrowly

The contract at the centre of the federal fight is Kalshi's CONTROL rulebook, self-certified on 12 June 2023 as "Will <chamber of Congress> be controlled by <party> for <term>?". On 22 September 2023 the CFTC issued an order prohibiting it from being listed, finding, as the Commission's 2026 proposal summarises it, that the contracts involved gaming and activity unlawful under state law and were contrary to the public interest.

• District court, 6 September 2024. In KalshiEX LLC v. Commodity Futures Trading Commission, Civil Action No. 23-3257 (JMC), Judge Jia M. Cobb granted Kalshi's motion for summary judgment, denied the Commission's cross-motion, and ordered that the September 2023 order is "hereby VACATED". The memorandum opinion followed on 12 September 2024.
• D.C. Circuit, 2 October 2024. In No. 24-5205, a panel of Judges Millett, Pillard and Pan dissolved the administrative stay it had entered on 12 September and denied the Commission's motion for a stay pending appeal, "without prejudice to renewal should substantiating evidence of irreparable harm arise". That is a ruling on a stay, not on the merits.
• Dismissal, May 2025. The Commission's own 2026 proposal records that its motion to dismiss the appeal was granted in May 2025 and the case closed, citing the D.C. Circuit's disposition of 7 May 2025. The district court's vacatur therefore stands without an appellate decision on the merits.
• Proposed rule, June 2026. The CFTC issued Prediction Markets; Public Interest Determinations on 10 June 2026, RIN 3038–AF65, published at 91 FR 35806 on 12 June 2026, with comments closing 27 July 2026. It proposes a definition of "gaming" under which "political elections are not gaming", states the Commission's preliminary view that its 2023 Kalshi order and an earlier Nadex order "were incorrect to find that event contracts involving political elections were event contracts that involve gaming", and lists "Results of political elections" among contracts that would generally fall outside the rule. It is a proposal until a final rule is published under the same RIN.

None of this is state law. Whether a state may act against a federally designated exchange's election contracts is a separate question — the Ninth Circuit's August 2026 decision in KalshiEX v. Assad remanded Nevada's challenges to those contracts to the district court — and the prediction market venues category page and why a venue is unavailable where you are keep that thread dated. What any of it means for the legal character of an event contract is on event contract or swap.

What it costs

Not the fee, which is the same as on any other contract of the venue's: the cost particular to election contracts is time and size.

• Time. Absent four qualifying calls, a Kalshi House-control position is held until 10:00 AM ET on 1 February 2027 and paid by the next day unless the outcome is under review. A Polymarket control market with an undeclared independent can run to 11:59 PM ET on 4 January 2027. A disputed Polymarket resolution adds four to six days. A contested race on Polymarket US's first-round terms may stay open until it is determined, up to two years.
• Size, on PredictIt. CFTC Letter No. 25-20 of 14 July 2025 sets the limit for one participant in one contract at the Federal Election Campaign Act limit on individual contributions, which the letter gives as $3,500 and which the Federal Election Commission adjusts for inflation every two years.
• Size, on Kalshi. The CONTROL terms set a position limit of $125,000 per member for individuals, $5,000,000 for entities and $50,000,000 for eligible contract participants, doubled for a demonstrated hedging need.
• Size, on Polymarket US. The first-round Senate terms set a position accountability level of $25,000 of notional exposure, with no position limits and margin at 100% of the amount at risk.
• The price of an objection, on Polymarket. A dispute is a bond, refundable only if the dispute succeeds. The Gamma API's umaBond field reads 10000 on the House-control markets and 2500 on the Georgia Senate markets.

What you can do about it

Read the market's rules page before the position, not the title. On Kalshi the one-line rules and the link to the filed terms are in the market and series objects of the public API — rules_primary, rules_secondary, contract_terms_url and settlement_sources — and reading a market's rules from the API shows where. On Polymarket read the market's description and check the oracle for any clarification. On Polymarket US read the market rules and the product terms they link to. On PredictIt open the Rules tab: the headline only approximates it.

Know which event the contract names. Write it down in one line before you trade: a call by four of eight named organisations, a call by three named outlets, a certified count, a sworn-in senator, a Speaker on 1 February, or the Clerk's certified totals. Two contracts on the same race that name different events are different contracts, and on election night they can trade at different prices without anyone being wrong — the general case is why the same contract costs two prices.

Know the close time and the latest expiration. Find when trading stops, when the contract expires if nothing happens early, and what holds it open: a runoff, a recount, an independent's caucus decision, a review. Money in a contract that has not settled is not money you can withdraw, and the latest date is the one to plan around.

Know the no-majority and the vacancy clauses. On the House the venues give three different answers to a chamber nobody controls outright, and one of them pays no party at all.

Know who may hold it where. Polymarket's international platform blocks the United States by physical location; Polymarket US serves US residents after identity verification; PredictIt is open only to US persons, at $3,500 a contract; Kalshi serves the US and most other countries except the jurisdictions its member agreement restricts. Each election series on Kalshi also carries its own list of prohibited traders — candidates, campaign and party staff, election officials, anyone able to see official counts before they are public, and employees of major decision desks — and Polymarket US's filed terms bar candidates and their campaign committees.

If you think a resolution is wrong, know where the window is. On Polymarket the window is the two-hour challenge period, and the objection costs a bond. On Kalshi, Polymarket US and PredictIt there is no window: raise it with the exchange before expiration, in writing, against the clause you are relying on. The per-venue resolution detail, each dated to the document it was read from, is in the prediction market venues listing and on the settlement source entry.