Polymarket sues Ohio over its sports contract crackdown: is Polymarket legal in Ohio?
Polymarket US sued Ohio’s attorney general and casino regulators in federal court on 16 October, the day the state’s cease-and-desist deadline ran out. It says Ohio’s licensing rules shut out-of-state firms out and that federal law overrides them. The lawsuit, Ohio’s new warning to sportsbooks and where Polymarket stands in Ohio.
In this article
Polymarket has sued Ohio to stop the state from shutting down its sports contracts. QCX LLC, which does business as Polymarket US, filed the lawsuit on 16 October 2026 in the US District Court for the Southern District of Ohio, the same day the state's deadline for prediction markets to stop offering sports event contracts ran out. The case is before Judge Douglas R. Cole.
Who is being sued
The suit names Ohio Attorney General Andy Wilson, the Ohio Casino Control Commission's interim executive director and the commission's members, all in their official capacities. It asks the court to declare Ohio's gambling laws unconstitutional and pre-empted as applied to Polymarket US, and to block the state from enforcing them.
Polymarket's two arguments
- Discrimination against out-of-state firms. Ohio reserves online sports gaming licences for businesses with a presence in the state, Polymarket argues, so it could never obtain the licence Ohio demands. Enforcing a licence it cannot get, it says, violates the Constitution's Commerce Clause.
- Federal law comes first. Polymarket US runs a CFTC-regulated exchange, and it argues that the Commodity Exchange Act gives the CFTC exclusive authority over its contracts. The filing leans on the CFTC's October move to write event contracts into the federal definition of a swap (the CFTC proposal).
The commerce argument is the new angle. The pre-emption argument is the one Kalshi lost at the Sixth Circuit on 25 September, a ruling that binds federal courts in Ohio.
How Ohio got here
| When | What happened |
|---|---|
| 25 September 2026 | The Sixth Circuit rules that Ohio can enforce its gambling laws against Kalshi's sports contracts |
| 2 October | The Casino Control Commission sends cease-and-desist notices to ten operators: Polymarket, Underdog, Gemini Titan, Coinbase, ProphetX, Novig, Robinhood, Plus500, Moomoo and Webull |
| 16 October | The compliance deadline passes; Polymarket files its lawsuit |
| 20 October | The commission warns licensed sportsbooks, suppliers and service providers that working with prediction markets could affect their licences, and gives them until 30 October to comply |
The notices warned of penalties up to the money an operator made from sports contracts in Ohio. Governor Mike DeWine has said the attorney general will sue operators that do not comply (Ohio's deadline).
Is Polymarket legal in Ohio?
Polymarket US is a federally regulated exchange, and Ohio's dispute is about sports contracts, not the rest of the platform. As of 21 October, reports said most of the ten notified platforms had not confirmed that they had stopped. Polymarket's lawsuit asks for an order blocking enforcement while the case runs; no ruling had been reported by 23 October. If a court sides with Ohio, sports contracts could be switched off for Ohio users, as has happened in other states. The national picture: is Polymarket legal in the US? · how to use Polymarket in the US.
Election markets are not part of the dispute. Ohio's own races remain some of the most traded: Ohio governor race odds · Ohio Senate race.
