Missouri orders Kalshi, Polymarket and four other prediction markets to stop taking sports bets

Missouri Attorney General Catherine Hanaway's office announced on September 18, 2026 that it had sent cease-and-desist letters to six prediction-market operators, ordering each to stop offering sports-outcome "event contracts" to Missouri residents. The letters went to Polymarket, Kalshi, Crypto.com, Novig, Underdog and Robinhood. Hanaway's office argues the contracts amount to unlicensed sports wagering under the law Missouri voters approved as Amendment 2 in November 2024, the same law that put the state's regulated retail and online sportsbooks live on December 1, 2025.

The letters give each company 30 days to comply, either by obtaining a license from the Missouri Gaming Commission or by ceasing to offer sports-related event contracts to Missouri users, according to Hanaway's office. The office said a company that does not comply will face enforcement action from the state.

What the state says it's owed

Hanaway's stated rationale rests on three specific gaps she says unlicensed operators avoid: the 10% wagering tax Missouri collects from licensed sportsbooks, the licensing and background-check process every Missouri sports wagering operator undergoes, and age verification that is supposed to keep wagering to bettors 21 and older. None of the six companies named holds a Missouri sports wagering license, per the attorney general's office.

Part of a broader, unsettled fight

Missouri's action joins a national fight this desk has tracked through several rulings that have not landed the same way twice. The Ninth Circuit ruled on August 28, 2026 that Nevada can enforce its gambling law against Kalshi's sports contracts, and a separate Ninth Circuit panel revived two California tribes' bid to block Kalshi from their land on September 16, 2026. Meanwhile the CFTC has twice invoked emergency authority to keep Kalshi operating in New York and Michigan over state objections, and a different appeals court had earlier sided with Kalshi's federal-preemption argument in New Jersey's case, a split now pending before the U.S. Supreme Court on New Jersey's petition. Missouri's letters are an attorney general's cease-and-desist rather than a lawsuit or a court ruling, so they do not resolve anything a court has already split on; they add a state regulator's position to a fight where outcomes have gone both ways depending on the court and the state.

What we could not verify

We have not independently reviewed the text of the six letters. Our account of their contents rests on Hanaway's office's public statement and consistent reporting from Missouri television and newspaper outlets that covered the announcement the same day. None of the six companies had issued a public response we could locate as of this writing. This does not change the status of Missouri's regulated sports betting market, which remains licensed and open, or its online casino market, which remains unauthorized.