Kalshi vs Polymarket, same question
Both venues are searched for the same topics every 6 hours. Markets that ask the same thing are paired and their YES prices placed on one 0–100¢ ladder, so the gap is visible. Look-alikes that fail a matching rule are listed below with the reason.
- Matched pairs
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- Median gap
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- Widest gap
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- Markets scanned
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- Look-alikes refused
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Matched pairs
Refused look-alikes
Titles that share most of their words but ask a different question. Pairing them would show a gap that means nothing. Each row shows the first rule it failed.
| Kalshi | Polymarket | Rule failed | Overlap |
|---|
How a pair is made
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Search the same words
Each topic runs through both venues' public search. Titles are tokenized, stop words dropped, and long forms folded together ("Federal Reserve" →
fed). -
Score by rare words
Similarity is Jaccard weighted by how rare each word is in the result set, so "nominee" counts for more than "2026". Pairs are one-to-one.
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Refuse look-alikes
Twelve rules make a pair agree on dates, place, stage (nominee vs confirmed), thresholds, direction, negation and more. Close times must line up too. Each rule has a regression test built from real titles.
A gap is not an arbitrage. Venues define and resolve events differently: being nominated isn't being confirmed, a price on one date isn't a price on another, and fees, limits and settlement differ. Use a pair as a lead, then read both rule books.