Wisconsin DOJ sues five trading platforms, alleging event contracts operate as illegal sports wagers

Wisconsin's Department of Justice filed three complaints in Dane County on April 24, 2026, accusing five trading and cryptocurrency platforms of offering "event contracts" that the state says function as illegal sports wagers and gambling activities conducted without required state licenses; prosecutors likened transaction fees to a house edge ^{[1] [2] [3]}.

The suits name Kalshi, Coinbase, Polymarket, Robinhood and Crypto.com and seek injunctions to halt the challenged event-contract offerings while the state pursues enforcement actions ^{[4] [1] [2]}.

Defendants have pushed back: Kalshi argued that federal law and Commodity Futures Trading Commission oversight preempt state regulation of prediction markets, and Coinbase cited a Third Circuit ruling it says limits state-by-state control of derivatives—legal positions the companies say place these markets outside Wisconsin's authority ^[3].

The Wisconsin complaints add to mounting regulatory scrutiny of prediction markets, coming as other jurisdictions have pursued related cases; no court rulings were reported at the time of filing ^{[5] [2]}.