Glossary › Arbitrage
Checked September 25, 2026 · 4 sources · plain-English definition, not financial advice
Arbitrage: Trying to lock in a profit from mismatched prices, such as between related Kalshi markets or between Kalshi and another venue, whatever the outcome.
The CFTC glossary defines arbitrage as the simultaneous purchase and sale of identical or equivalent contracts across markets to benefit from a price discrepancy. Within one Kalshi market there is no gap between Yes and No to exploit: Kalshi's help center says buying Yes and selling No are the same thing, and its API treats a No bid at 30¢ as a Yes ask at 70¢.
Opportunities, when they appear, are between related markets or venues. Worked example: an event has three candidate markets whose Yes asks are 30¢, 33¢ and 32¢, 95¢ in total. Buying one Yes of each pays $1 if one of them wins, a 5¢ gross edge. But Kalshi's own collateral return example shows that every market in such a group can resolve No, which would lose all 95¢, and fees on three orders can eat the rest.
Across venues, such as Kalshi and Polymarket, contracts that look alike can use different sources, deadlines and rules, so a price gap is not risk free. What to check: that the contracts are truly equivalent, the fees and spreads on every leg, and whether each leg can be filled at the quoted size.
Kalshi vs Polymarket odds · Kalshi fee calculator
Checked September 25, 2026. Kalshi changes fees, rules, funding options and limits; the market's rules, the order ticket and Kalshi's help center are the final word.
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