Sports prediction markets face uneven legal access across US states

CBS Sports mapped the legal status of sports event contracts on Kalshi and Polymarket across all fifty states, and the picture that emerged is less a regulatory framework than a patchwork — some states open, some explicitly closed, most somewhere in between with no clear answer on the books.

Washington is the most visible case. Kalshi has already blocked its residents from sports event contracts following pressure from state regulators, and the injunction fight in federal court is ongoing. That is a resolved question, at least for now. What the CBS Sports survey makes clear is how many states have not resolved anything — they simply haven't been tested yet.

That asymmetry is the part the market has not priced correctly. The states that have blocked access did so because a regulator moved, a lawsuit was filed, or a specific contract drew attention. The states that currently allow access have not affirmatively permitted anything — they have simply not acted. Those are not the same thing, and treating them as equivalent is a category error that will matter when the next high-profile contract draws scrutiny in a state that hasn't yet declared a position.

Kalshi's preemption argument — that federal designation as a CFTC-regulated exchange shields it from state gambling law — is the thesis that the open-state map depends on. If that argument holds at the circuit level, the patchwork collapses in Kalshi's favour. If it doesn't, the default position for most of those undecided states is that sports event contracts look like sports betting, and sports betting without a state licence is illegal. The 6th Circuit case is the fulcrum, and we don't have a ruling.

What I keep coming back to is liquidity concentration. When a market is accessible in some states and blocked in others, volume doesn't distribute evenly across the remaining open states — it clusters, usually in the largest remaining markets. That creates thinner books in mid-size states, which degrades price quality for everyone, which in turn makes the contracts less useful as information mechanisms. I've seen this pattern in early-stage exchange products before, where geographic restrictions weren't fatal but they were expensive in ways that only became visible after the fact.

The CBS Sports framing treats this primarily as a consumer access question — which is fair and accurate as far as it goes. My read is that it's also a market structure question. Prediction markets on sporting events are most accurate when they're liquid, and they're most liquid when the addressable population is largest. Every state that blocks access without a federal preemption ruling doesn't just reduce potential customers — it degrades the signal quality of every contract that remains active.

Cantor Fitzgerald's institutional block-trading launch on Kalshi, aimed at getting larger players into these markets, is the supply-side answer to this problem. Better pricing from institutional participants can partially offset the liquidity drag from restricted retail access. Whether it offsets enough is the position I'm watching.