Polymarket US sues Missouri officials in St. Louis federal court over sports event contracts

The company behind Polymarket's U.S. exchange has gone to federal court in St. Louis to stop Missouri from treating its sports event contracts as unlicensed sports betting, making it the fifth prediction-market operator to sue the state since its Attorney General sent cease-and-desist letters in September.

QCX LLC, which does business as Polymarket US, filed its complaint on November 9, 2026 in the U.S. District Court for the Eastern District of Missouri (docket, No. 4:26-cv-01930). It names Attorney General Catherine L. Hanaway, Missouri Gaming Commission chair Jan M. Zimmerman and commissioners Kevin M. Spaulding, Kevin Cantwell, Sam Gladney and Roger Stottlemyre. The complaint says that after the letter, Polymarket US "conferred with the Attorney General's office in an effort to resolve the State's demands without litigation," that those discussions were unsuccessful, and that with the 30-day deadline passed it faces "an imminent threat of enforcement."

What Missouri's letter demanded

The September 16 letter, attached to the complaint as Exhibit 1, calls Polymarket "an online sports wagering platform" and gives it two options: stop offering sports wagering to people located in Missouri, or obtain a Missouri Gaming Commission licence, pay state taxes and fees, and stop serving people under 21. It cites the state's 10% tax on adjusted gross revenue from sports wagering and licence and renewal fees of up to $500,000, and says Polymarket's U.S. rulebook lets anyone aged 18 trade, while Missouri rules impose an "affirmative duty" to prevent wagers by under-21s. The letter warns that otherwise "the State of Missouri will take legal action against Polymarket."

The company's two claims

Count I argues that the Commodity Exchange Act gives the CFTC exclusive jurisdiction over event contracts traded on a designated contract market, so Missouri law, including Article III, Section 39(g) of the state constitution, is preempted as applied. The complaint says the CFTC designated QCX as a contract market on July 9, 2025, and that since September 30, 2025 the exchange has self-certified financial, election-related and sports-related event contracts. It also points to the CFTC's November 5, 2026 interpretation that a designated contract market generally may not limit access based on a participant's location within the United States, which AskSpinner reported last week.

Count II argues that Missouri's regime discriminates against interstate commerce. According to the complaint, new Missouri sports-wagering licences are tied to gambling boats and sports teams located in the state, licensees' servers must be physically located in Missouri under 11 CSR 45-20.290(5), and licensed wagering is limited to people physically present in Missouri. Polymarket US says complying would turn its national exchange into "a one-State gambling portal." The complaint states that it does not seek to block the assessment or collection of any Missouri tax, while reserving the right to challenge taxes elsewhere.

The company asks the court for a declaratory judgment, preliminary and permanent injunctions barring enforcement of Section 39(g) and related laws against its federally regulated activities, and attorneys' fees under 42 U.S.C. § 1988. As of the afternoon of November 9 (ET), the public docket listed the complaint and its attachments, with no judge assignment or motion for preliminary injunction yet listed. The claims are allegations and have not been tested in court.

Five Missouri lawsuits

Court records on CourtListener show four earlier federal suits against Hanaway over the same campaign: North American Derivatives Exchange, which runs Crypto.com's OG prediction market (W.D. Mo., No. 4:26-cv-00969, filed October 16); Novig operator Ludlow Exchange (E.D. Mo., No. 4:26-cv-01780, October 16); Kalshi (E.D. Mo., No. 4:26-cv-01860, October 27), which has since asked for a temporary restraining order; and Underdog Exchange DCM (W.D. Mo., No. 2:26-cv-04300, November 8). The cases are listed in AskSpinner's prediction-market litigation tracker.

Updated November 10, 2026: Restated the docket check in Eastern Time and limited the filing description to the complaint and its attachments on the public docket.