Authorities in Nevada and Ohio have experienced some success in their attempts to reign in prediction market trading within their borders, so authorities in Wisconsin are looking to join that fray. Wisconsin’s attorney general has filed lawsuits in state court against five defendants, including Kalshi and Polymarket.
The actions seek a declaratory judgment that designated contract markets on exchanges like Kalshi and Polymarket are tantamount to sports wagers and ask the court to enjoin the defendants against offering them in Wisconsin. It’s a narrower approach than other state governments have taken, and that could differentiate the litigation moving forward.

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Wisconsin Attorney General Josh Kaul issued a press release on Thursday, announcing his filing in Dane County’s Superior Court. The three complaints collectively name Coinbase, Crypto.com, Kalshi, Polymarket, and Robinhood as primary defendants.
Kaul’s statement cites Wisconsin’s public nuisance statute and characterizes designated contracts markets (DCMs) based on the outcomes of sporting events provided by the defendants as “illegal sports bets.” Kaul adds that his filings ask the court for “preliminary and permanent injunctions enjoining and restraining the defendant companies from making sports-related event contracts available for trading by customers located in Wisconsin.”
Sports wagering in Wisconsin at tribal casinos within the state’s borders has been regulated since 2021, and the legislature recently expanded that tribal gaming to include online sports wagering across the state as well. Kaul’s focus on DCMs related to sports represents a different strategy than his counterparts in other states have taken.
A point of differentiation for Kaul’s filings compared to those that gaming regulators and law enforcement in other U.S. states have brought before courts is more about what the state of Wisconsin isn’t arguing in these complaints than the case it is making. Kaul isn’t challenging whether all DCMs by definition fit the description of gambling under Wisconsin law.
Rather, his complaints narrowly focus only on those DCMs that pertain to outcomes of sporting events. The argument to the court is that now that Wisconsin is regulating online sports wagers, Kaul has authority to enforce those statutes against the defendants because their products are functionally similar to sports bets from his perspective.
In doing so, Kaul somewhat simplifies the questions before the court of whether DCMs fit Wisconsin’s definition of sports wagers and whether the defendants making them available violates Wisconsin’s public nuisance law. With that strategy, Kaul likely hopes to avoid a broader consideration of Wisconsin’s authority to regulate DCMs.
Regardless, the defendants are likely to stick with their argument that sports-based DCMs fit the definition of “swaps” under federal law in the U.S., and therefore federal statutes give explicit and exclusive oversight of the markets to the U.S. Commodity Futures Trading Commission. That argument could be made in a federal court soon.
Kalshi, and to a lesser extent Robinhood, have been proactive in asking federal district courts for the same kind of injunctive relief they secured against New Jersey. A similar petition could be forthcoming in the eastern or western districts of Wisconsin soon.
In the end, this action by Kaul may prove to be little more than another preliminary event that helped to set the stage for a U.S. Supreme Court decision. For now, though, Kaul is trying to join officials in Nevada and Ohio who have seen limited success in restricting prediction market operation.
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