Wisconsin AG Sues Kalshi, Polymarket, Robinhood, Crypto.com and Coinbase
Wisconsin Attorney General Josh Kaul filed suit in state court seeking permanent injunctions against all five major US prediction market platforms, arguing event contracts constitute unlicensed gambling under state law regardless of federal CFTC licensing.
Wisconsin Attorney General Josh Kaul filed suit in state court against Kalshi, Polymarket, Crypto.com, Robinhood, and Coinbase in late April 2026, seeking preliminary and permanent injunctions barring the platforms from operating in Wisconsin. The filing is the broadest state-level legal challenge to prediction market operators in the industry's history, targeting every major US-accessible platform in a single action.
Kaul's complaint frames event contracts as unlicensed gambling under Wisconsin law, regardless of the federal CFTC Designated Contract Market licences held by some defendants. "Thinly disguising unlawful conduct doesn't make it lawful," Kaul said at the announcement. The theory forces a collision with federal pre-emption doctrine: Kalshi and Robinhood both hold DCM licences and have argued that federal CFTC oversight supersedes state gaming statutes. Courts have not resolved this pre-emption question definitively, and the Wisconsin case is expected to become a key test of whether state gaming authorities can override a federal commodity exchange licence.
For Wisconsin residents, even a preliminary injunction would block access to all five named platforms while litigation proceeds. The stakes are significant given Kalshi's current availability in 35+ US states and Robinhood's 26-million-strong user base. Kaul's office did not specify remedies for existing Wisconsin account holders. Legal observers noted that New Jersey has already maintained a de facto exclusion of CFTC-licensed event contract platforms through its own regulatory posture, suggesting Wisconsin is following a precedent rather than acting in isolation.
At least three other state attorneys general have signalled interest in similar suits following Wisconsin's filing. The action coincides with a 24% reduction in CFTC staffing since January 2025, a capacity cut critics say has created a regulatory vacuum that states are beginning to fill. If Wisconsin prevails on the pre-emption question, federal DCM licences would lose much of their value as a shield against state gaming laws, potentially dismantling the geographic access model under which US prediction market platforms currently operate.
Operators mentioned in this article
CFTC-regulated Kalshi
First fully CFTC-regulated US event-contract exchange.
Crypto / On-chain Polymarket
USDC-settled on Polygon. Largest prediction market by volume.
Broker (Embedded Contracts) Robinhood
Consumer brokerage offering embedded event contracts. Fastest-growing retail prediction market platform in the US.
Recent updates
Missouri AG Sends Cease-and-Desist Letters to Six Prediction Market Operators
Missouri Attorney General Catherine Hanaway issued cease-and-desist letters on September 18 to six prediction market operators — Kalshi, Polymarket, Robinhood, Crypto.com, Novig, and Underdog — alleging their sports event contracts constitute unlicensed sports wagering under Missouri law. The letters give platforms 30 days to comply or obtain licenses from the Missouri Gaming Commission. Missouri is the broadest multi-platform C&D action to date, targeting all major operators simultaneously. The action arrives one day after Montana and Kalshi filed a joint stipulation in which Montana agreed to pause enforcement while Ninth Circuit en banc review is pending.
Yahoo Finance Ends Polymarket Data Partnership After Five Months
Yahoo Finance and Polymarket mutually ended their prediction market data partnership on September 18, approximately five months after the companies announced an exclusive arrangement in November 2025. The Polymarket data hub that Yahoo Finance launched in January-February 2026 was quietly taken down in April 2026. No reason was publicly disclosed. Yahoo Finance retains an advertising relationship with Polymarket. The partnership's end is a setback for Polymarket's strategy of embedding its probability data into mainstream financial media platforms.
Montana and Kalshi Reach Joint Stipulation — State Pauses Enforcement Pending Ninth Circuit En Banc
Kalshi dismissed its lawsuit against the Montana Department of Justice on September 17 after both sides filed a joint stipulation in which Montana agreed to pause all enforcement, investigations, and cease-and-desist proceedings against Kalshi's event contracts. The pause lasts until the Ninth Circuit either denies en banc review of the August 28 ruling or issues an en banc decision. Montana must give Kalshi 30 days written notice before resuming any enforcement action after that window closes. The agreement mirrors the Robinhood-Michigan stipulation from September 4 and reinforces a pattern of states reaching negotiated compliance pauses while the appellate process plays out.