In a one-winner Kalshi event, exactly one outcome settles at 100¢, so the whole field should cost about 100¢ to buy. When it costs less, that’s an underround, a lock: priced-in profit before fees and fills. This page scans every one-winner field continuously, updated every few minutes.
Common questions
What is a lock on Kalshi?
A lock is a one-winner event whose outcomes collectively cost less than 100 cents to buy, an underround. Since exactly one outcome must settle at 100 cents, buying the whole field below 100 cents is priced-in profit, before fees and fills.
Why do underrounds appear?
Usually because one outcome's quote goes stale or a thin book drifts while attention is elsewhere. They're structural mistakes, which is why they're rare and vanish within minutes of being noticed.
Is a Kalshi lock really free money?
Not automatically. The per-contract fee can erase a thin underround, filling every leg at size moves prices against you, and a stale quote on one thin outcome can fake the whole thing. Every leg needs verifying on Kalshi at executable prices before it's real.
How do I find Kalshi arbitrage opportunities?
Scan every one-winner event's full field cost continuously. That's what this page and the Value Scanner do, and Pro users can get an email within minutes of an underround appearing, which matters because locks rarely survive long.
Related: the Value Scanner (full pricing-tightness board), underround and lock in the glossary, and the arbitrage calculator. Research signal, not financial advice.