Kalshi runs hundreds of threshold ladders: above $60,000, above $65,000, above $70,000, all on the same event, all settling together. Those prices are not independent opinions. Clearing $70,000 means you have already cleared $65,000. So the higher strike can never be more likely than the lower one.
When the order book breaks that rule, it is not a signal or a difference of view. It is a logical impossibility, and it can be harvested with a position that pays in every outcome. This page scans every live ladder for one.
Why it pays no matter what
Say the book prices above 70k at 55¢ and above 65k at only 48¢. Buy YES on 65k for 48¢ and NO on 70k for 45¢. You have spent 93¢. Now walk through every way the world can end:
It settles below 65kyour NO pays$1.00
It settles between 65k and 70kBOTH legs pay$2.00
It settles above 70kyour YES pays$1.00
There is no fourth case. You spent 93¢ and the worst you can collect is $1.00. That is not a good bet, it is not a bet at all. Everything below is computed with Kalshi’s fees charged on both legs, so an inversion too small to beat the fees is never shown.
Checking every live ladder for impossible pricing…
The honest caveats
The payoff is guaranteed by logic. The execution is not. Three things can spoil it, and we would rather you hear them from us: the quote may not be fillable at any real size, so we flag thin books rather than hiding them; the mispricing can disappear between placing your first leg and your second, which leaves you with a naked position instead of an arb; and your capital is tied up until the event settles, so a 4% risk-free return over a month is a different animal from one over a day. Confirm both quotes on Kalshi before you place anything. This is not financial advice.
Building a parlay instead? The combo evaluator grades your legs and finds the hedge. Want to know what a price actually means? The Truth Machine measures it from settled outcomes.