When Two Markets Disagree: Cross-Market Spreads Explained

Sometimes the same real-world question is listed on more than one platform — and the two prices don’t match. Polymarket might have it at 48% while Kalshi has it at 54%. That six-point gap is a cross-market spread, and it is one of the more interesting things you can watch.

Why the gap exists

In a perfectly efficient world the two prices would be identical, because you could profit from the difference until it closed. In the real world several frictions keep them apart: the platforms have different traders and different amounts of money, they charge different fees, moving money between them takes time and effort, and one of them may simply be slower to react to news. So a spread can persist even when everyone can see it.

What a spread tells you

• A disagreement between two independent crowds. When they diverge sharply, at least one is probably mispricing the question — the spread flags where to look closer.
• Which side looks “cheaper.” If “yes” is 48% on one venue and 54% on the other, yes is cheaper on the first — useful context even if you never act on it.
• How settled a question is. Tight spreads suggest the two crowds agree; wide, volatile spreads suggest genuine uncertainty.

WyldMarkets computes these spreads automatically for events that trade on both platforms, so you can see the disagreement — and its size — without checking two sites.

A spread is information about two markets, not a trading recommendation. Nothing here is financial or betting advice.