Kalshi vs Polymarket: Will Josh Shapiro be the Democratic Presidential nominee in 2028
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
- 0.0 pts
- Match confidence
- 95%
- Theoretical edge
- none
Side by side
Probability history
How confident is this match?
- Title
- 79%
- Entities
- 50%
- Dates
- 100%
- Threshold
- 100%
- Polarity
- 100%
- Rules
- 65%
Deterministic score 78%. Semantic verification 95%. Last verified Sep 22, 08:05 ET.
- The Kalshi contract explicitly lists 'https://democrats.org/' as the resolution source, while the Polymarket contract states it will use a 'consensus of official Democratic Party sources'. These are functionally equivalent but not textually identical.
- The Polymarket rules include an explicit clause: 'Any replacement of the democratic nominee before election day will not change the resolution of the market.' The Kalshi rules do not contain this specific exclusionary language, although standard interpretation of 'wins and accepts' usually implies the initial winner. However, without the explicit clause, there is a theoretical edge case where if a
- The Polymarket rules include an explicit clause: 'Any replacement of the democratic nominee before election day will not change the resolution of the market.' The Kalshi rules do not contain this specific exclusionary language, although standard interpretation of 'wins and accepts' usually implies the initial winner/acceptor is the subject. However, without the explicit clause, there is a minor nu
- Kalshi close/settlement time is 2028-11-07 15:00 UTC, while Polymarket close time is 2028-11-08 04:59 UTC (approx. 14 hours later).
- Polymarket explicitly states that replacement of the nominee before election day does not change resolution; Kalshi rules are silent on this specific edge case but imply settlement based on the initial winner/acceptance.
- Resolution sources differ slightly in specificity: Kalshi cites 'https://democrats.org/', while Polymarket cites 'consensus of official Democratic Party sources'.
- The Kalshi contract explicitly lists the resolution source as 'https://democrats.org/', whereas the Polymarket contract states it will use a 'consensus of official Democratic Party sources'. While functionally similar, the specific citation differs.
- The Kalshi close/settlement time is 2028-11-07 15:00 UTC, while the Polymarket close time is 2028-11-08 04:59 UTC. This creates a ~14-hour window where one market may be closed/settled while the other remains open, though both occur after the likely nomination acceptance (July/August) and before the general election cutoffs implied by the dates.
- The Kalshi contract explicitly requires the nominee to 'accept' the nomination for a YES resolution. The Polymarket contract also requires the individual to 'win and accept' the nomination.
- The Polymarket contract includes a specific clause stating that any replacement of the Democratic nominee before election day will not change the resolution (i.e., if Shapiro wins/accepts but is later replaced, it still resolves YES). The Kalshi rules provided do not explicitly mention this replacement scenario, but standard interpretation of 'wins and accepts' usually implies the initial act of a
Both contracts resolve YES if Josh Shapiro wins and accepts the 2028 Democratic presidential nomination. The core condition (winning and accepting) is identical. The Polymarket contract adds a clarification about replacements which aligns with standard market practices for such events, making them effectively equivalent for settlement purposes despite minor differences in stated resolution sources.
Theoretical cross-market edge
Why are these diverging?
Explanation pending
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