Grade C · 0%RelatedOutcome mapping: same

Kalshi vs Polymarket: Czechia 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.

Live comparison
Kalshi
1.0%
—
Polymarket
99.4%
—
Disagreement
98.4 pts
Match confidence
0%
Theoretical edge
none

Side by side

MetricKalshiPolymarket
Probability1.0%99.4%
1h move——
24h move——
7d move——
24h volume$1.06M$1.60M
Liquidity—$86,425
Spread——
Open interest926,750—
ClosesOct 3, 16:44 ETOct 3, 14:45 ET
Resolution sourcehttps://www.espn.com/https://www.uefa.com/uefanationsleague/
ContractOpen →Open →

Probability history

Both venues on one axis, with the gap beneath
KalshiPolymarket
No history available for this range yet.

How confident is this match?

Deterministic scoring first; the model may only downgrade
Title
61%
Entities
100%
Dates
86%
Threshold
100%
Polarity
100%
Rules
35%

Deterministic score 76%. The model read both rule sets and did not find the contracts equivalent. Last verified Oct 3, 15:03 ET.

Soft flags
  • resolution_sources_differ
  • tie_handling_differs
  • data_release_rules_differ

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.

Material differences
  • The Kalshi contract asks if Czechia wins, while the Polymarket contract asks if Spain wins.
  • Kalshi explicitly states that extra time and penalties are excluded (resolution based on 90 minutes + stoppage). Polymarket also specifies 'first 90 minutes of regular play plus stoppage time', so this aspect is similar, but the primary question polarity is opposite.
  • Kalshi has a specific 'Tie' market for draws. Polymarket resolves to 'No' if Spain does not win (which includes draws and losses).
  • Kalshi resolves to a 'fair price' if the game is cancelled or rescheduled >48 hours away. Polymarket remains open until completion if postponed, and resolves 'No' if cancelled entirely with no make-up game.
  • Resolution sources differ: Kalshi uses ESPN; Polymarket uses UEFA official stats, then Flashscore/Sofascore.
  • Kalshi asks if Czechia wins; Polymarket asks if Spain wins.
  • Kalshi YES pays only on a Czechia win. Polymarket NO pays on both a Czechia win and a Draw.
  • Resolution sources differ (ESPN vs UEFA/Flashscore).
  • Cancellation rules differ (Fair price vs No/Remains open).
  • The Kalshi contract asks if **Czechia** wins, while the Polymarket contract asks if **Spain** wins. These are mutually exclusive outcomes in a soccer match (excluding draws).
  • Kalshi explicitly states that ties resolve to 'No' for the Czechia market (and have a separate Tie market), whereas Polymarket resolves 'No' for Spain if they do not win (which includes ties and losses).
  • Resolution sources differ: Kalshi uses ESPN; Polymarket uses UEFA official stats with fallbacks to Flashscore/Sofascore.

The contracts ask opposite questions (Czechia wins vs Spain wins). A trader holding YES on Kalshi (Czechia wins) would be paid in the same scenario as holding NO on Polymarket (Spain does not win), assuming no draw handling differences affect the binary payout structure directly. However, they are not equivalent because one is about Czechia's victory and the other about Spain's victory. The mapping 'kalshi_yes' -> 'polymarket_no' reflects that Czechia winning implies Spain did not win. But strictly speaking, they are not the same event outcome definition (one focuses on Team A, one on Team B).

Theoretical cross-market edge

Grade A pairs only, from executable book prices with depth simulation
Theoretical edge is calculated only for Grade A pairs, where the two contracts appear materially equivalent for settlement analysis. This pair is graded C, so the venues are compared for probability and sentiment only.

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

No timeline events yet

Timeline entries appear once price or trade activity crosses a reporting threshold.

Notable trades on both venues

Past 24 hours, ranked by notional

No sizeable trades recorded

Neither venue has printed a trade above the reporting threshold on this event in the last 24 hours.