PANews reported on April 24 that, according to CoinDesk, Wisconsin has filed a lawsuit against Kalshi, Coinbase, Polymarket, Robinhood, and Crypto.com, accusing their prediction markets of being unlicensed gambling operations. The state attorney general stated, "A weak disguise does not legalize illegal activities." The complaint alleges that the platforms' event contracts meet the definition of betting under Wisconsin law and cites Kalshi's claim of being "the first legal sports betting platform in the country" and Polymarket's claim of being "a platform where people can bet on the outcome of future events" as evidence.

The core issue in this case is whether the contracts on the platform are financial instruments governed by the CFTC or bets governed by state gambling laws. This dispute is likely to ultimately reach the Supreme Court. Previously, states such as Nevada and New York have taken similar positions, while the Third Circuit Court of Appeals upheld Kalshi's position.