The Wisconsin Department of Justice has filed lawsuits against Kalshi, Robinhood, Coinbase, Polymarket, Crypto.com and affiliated entities, seeking to stop the companies from offering sports-related event contracts to customers in Wisconsin.
The complaints, filed in Dane County, allege that the companies are facilitating illegal sports betting by presenting sports wagering activity as event contracts. Wisconsin law prohibits most commercial gambling, with sports betting permitted only in limited circumstances.
According to the DOJ, the contracts at issue pay out based on the outcomes of sports events and function in the same way as ordinary sports bets. The lawsuits allege that the companies collect a fee for each transaction, generating revenue from customers in Wisconsin through activity the state considers unlawful gambling.
Wisconsin Attorney General Josh Kaul said: "Thinly disguising unlawful conduct doesn't make it lawful."
The legal action comes amid wider scrutiny of prediction markets and sports event contracts in the US.
Operators in the sector have argued that event contracts fall under commodities and derivatives frameworks, while state regulators and tribal gaming interests have challenged the products where they resemble sports betting.
The complaints seek a court declaration that making sports-related event contracts available to customers in Wisconsin violates Wis. Stat. § 945.03(1m) and creates a public nuisance. The DOJ is also asking for preliminary and permanent injunctions to prevent the companies from offering those contracts in the state.
Kalshi is specifically referenced in the DOJ's statement, with the department citing reported annual revenue from sports contracts of more than $1bn, representing around 90% of its estimated annualized revenue.
The cases add to a growing legal divide between state gambling enforcement and federally regulated event-contract platforms, particularly as sports markets become a larger part of prediction market activity.
The Wisconsin action follows earlier litigation involving Kalshi and Robinhood in the state. In December 2025, a Wisconsin federal court denied Kalshi's request for expedited discovery in a case brought by the Ho-Chunk Nation Tribe over alleged illegal betting operations.
The DOJ is seeking both preliminary and permanent injunctions to stop sports-related event contracts from being offered to Wisconsin customers
