Polymarket US and Robinhood sue Missouri over sports event contracts

Polymarket US and Robinhood have each filed separate federal lawsuits against Missouri officials, challenging the state's attempts to block them from offering sports event contracts. The suits follow cease-and-desist letters sent in September 2026 by Missouri Attorney General Catherine Hanaway that targeted Novig, Polymarket US, Robinhood, Kalshi, Underdog and Crypto.com. Both plaintiffs seek court rulings to prevent enforcement of Missouri's measures against their operations.

What the lawsuits allege

Polymarket US asks a federal court to find Missouri's regulatory and licensing regime unconstitutional as applied to its business. The company argues the state's requirements violate the Commerce Clause of the US Constitution by restricting interstate commerce and specifically challenges a Missouri Gaming Commission rule that requires licensed operators to keep servers physically inside Missouri. Polymarket US also cites the Commodity Futures Trading Commission's November 5 impartial access interpretation, saying that geographic restrictions imposed to comply with state gambling laws are incompatible with exchange regulations.

Polymarket US requests both preliminary and permanent injunctions to stop Missouri from enforcing those requirements against it.

Robinhood's complaint advances a different statutory theory. The company contends that sports event contracts are financial products authorised at the federal level and therefore fall under the Commodity Futures Trading Commission's jurisdiction rather than state gambling laws. Robinhood argues federal law pre-empts Missouri regulation of these instruments and asks the court to bar the state from treating event contracts as unlicensed wagering.

"Missouri’s position rests on the premise that, despite express federal preemption and the CFTC’s comprehensive regulation of derivatives trading, event contracts listed on CFTC-regulated DCMs and facilitated by CFTC-registered FCMs constitute ‘wagering’ subject to Missouri gaming laws. Federal courts have long recognised that the CFTC’s regulation of the national derivatives market is exclusive and preempts state involvement," Robinhood counsel wrote in the lawsuit.

Background: cease-and-desist letters and state rules

Attorney General Catherine Hanaway issued cease-and-desist letters in September 2026 demanding that Novig, Polymarket US, Robinhood, Kalshi, Underdog and Crypto.com immediately stop offering sports-related contracts in Missouri. Hanaway said the contracts constitute unlicensed sports wagering under Missouri law, citing the sports betting framework the state launched in December 2025.

Missouri's current licensing model requires licensed online sportsbooks to geographically restrict operations to the state and to maintain data centres and corporate infrastructure within its borders. The state-level framework is the central target of both complaints.

Legal touchpoints cited by the plaintiffs

Both plaintiffs invoke federal pre-emption doctrines but from different angles. Polymarket US frames its challenge around the Commerce Clause and a specific Gaming Commission server-location rule. Robinhood relies on the CFTC's statutory authority over derivatives and the agency's regulatory reach for event contracts.

Polymarket US points to the CFTC's November 5 impartial access interpretation as support for its claim that state-imposed geographic restrictions clash with exchange rules. Robinhood emphasises the exclusive federal regulation of the national derivatives market and seeks a judicial declaration that Missouri law cannot be applied to event contracts listed or cleared under CFTC regimes.

The lawsuits set up a federal test of how state gambling frameworks interact with federal financial-market regulation and the constitutional limits on state regulation of interstate commerce. The named defendants in the filings are Missouri officials responsible for enforcing the state's gaming laws.