Kalshi vs Polymarket: Northwestern wins
Two contracts on the same event, priced by two separate crowds. Where they disagree, one of them is wrong — or the contracts are not quite the same question.
- Disagreement
- 98.4 pts
- Match confidence
- 0%
- Theoretical edge
- none
Side by side
Probability history
How confident is this match?
- Title
- 61%
- Entities
- 80%
- Dates
- 86%
- Threshold
- 100%
- Polarity
- 85%
- Rules
- 64%
Deterministic score 75%. The model read both rule sets and did not find the contracts equivalent. Last verified Oct 2, 23:02 ET.
- tie_handling_differs
A soft flag is an ambiguity the deterministic rules noticed but could not resolve. Any one of them keeps a pair out of Grade A.
- Tie handling: Kalshi rules do not explicitly specify tie resolution (implied 'fair price' or undefined if not a win/loss), whereas Polymarket explicitly resolves ties to 50-50.
- Postponement/Cancellation logic: Kalshi has a strict 48-hour window for postponed games; if the game starts after this window or is cancelled without starting within it, it resolves to 'fair price'. Polymarket remains open indefinitely until completion if postponed, and only resolves 50-50 if cancelled entirely with no make-up game.
- Outcome Mapping Ambiguity: The Kalshi contract asks 'Northwestern wins' (YES = Northwestern Win). The Polymarket contract is two-sided ('Penn State' vs 'Northwestern'). While 'Northwestern' on Polymarket corresponds to 'YES' on Kalshi, the structural difference in how non-win outcomes (ties/cancellations) are handled makes them not strictly equivalent for all scenarios.
- Tie handling: Kalshi rules do not explicitly state how a tie is resolved (though NCAA football rarely ends in a tie, the rule text is silent), whereas Polymarket explicitly resolves to '50-50' if the game ends in a tie.
- Cancellation/Postponement beyond window: Kalshi resolves to a 'fair price' if the game is cancelled or not started within 48 hours of the original start time. Polymarket remains open indefinitely until completion if postponed, and resolves '50-50' only if canceled entirely with no make-up game. This creates different settlement outcomes for long delays or cancellations.
- Resolution Source Specificity: Kalshi specifies `https://www.ncaa.com/sports/football/fbs` while Polymarket specifies `https://www.ncaa.com/`. While likely functionally similar, they are technically different URLs.
- Market Structure: Kalshi is a binary market on Northwestern winning (YES/NO). Polymarket is a two-sided market where YES corresponds to Penn State and NO corresponds to Northwestern. To map Kalshi YES (Northwestern wins) to Polymarket, one must buy Polymarket NO.
- Tie/Draw Handling: Kalshi rules do not explicitly define a tie outcome (implying 'No' if Northwestern does not win, or potentially ambiguous), whereas Polymarket explicitly resolves ties to 50-50.
- Cancellation/Postponement Handling: Kalshi resolves to a 'fair price' if the game is cancelled or not started within 48 hours of the original start time. Polymarket remains open indefinitely until completion if postponed, and resolves 50-50 only if cancelled entirely with no make-up game. This creates different settlement outcomes for long delays or cancellations.
- Outcome Mapping Ambiguity: The Kalshi contract asks 'Northwestern wins'. A YES on Kalshi corresponds to Northwestern winning. On Polymarket, the outcome labeled 'Northwestern' (which is the NO side of the binary market structure described in the prompt's extracted data, though typically Polymarket sports markets are multi-outcome or specific winner markets) pays if Northwestern wins. However, the…
- Tie handling: Kalshi rules do not explicitly state a tie outcome (implying 'Northwestern wins' is false if tied, or potentially fair price depending on interpretation of 'win'), whereas Polymarket explicitly resolves ties to 50-50.
- Cancellation/Postponement beyond window: Kalshi resolves to 'fair price' if the game is cancelled or not started within 48 hours of the original start time. Polymarket resolves to 50-50 if the game is canceled entirely with no make-up game, and remains open indefinitely if postponed (no 48-hour cutoff mentioned).
The contracts differ significantly in their handling of edge cases such as ties and postponements beyond 48 hours. Kalshi uses a 'fair price' mechanism for cancellations/postponements outside its window, while Polymarket uses a 50-50 split for ties and indefinite openness for postponements. Additionally, Kalshi's YES outcome (Northwestern Wins) maps to Polymarket's NO outcome (which represents Northwestern winning in the two-sided market structure where YES=Penn State).
Theoretical cross-market edge
Why are these diverging?
Explanation pending
An evidence-grounded explanation is written once this market gathers enough confirmed price and trade evidence. Every number on this page is already live.
Event timeline
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Notable trades on both venues
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