Polymarket US has filed a lawsuit against the state of Ohio, challenging the state's licensing requirements for sports event contracts. The prediction market exchange argues that federal law preempts Ohio's enforcement actions, positioning the case as a test of regulatory authority over federally regulated derivatives markets operating at the state level. Ohio regulators demanded an immediate halt to Polymarket's sports contract offerings in the state. As of October 19, no court order had been issued to shield the platform from enforcement action, leaving Polymarket operating without legal protection while the dispute unfolds. The outcome could set precedent for how state gaming authorities interact with federally chartered prediction markets nationwide.