California Attorney General Rob Bonta joined a bipartisan coalition of 37 attorneys general on Friday in filing an amicus brief supporting Ohio's right to enforce its state sports gaming and gambling laws against prediction market operator Kalshi. The brief, filed in the U.S.
Court of Appeals for the Sixth Circuit, backs Ohio gaming authorities in the case KalshiEx LLC v. Schuler et al.
Kalshi is appealing a federal district court's decision that denied its request for a preliminary injunction against the state. This marks the seventh time California has joined multistate amicus efforts targeting Kalshi and similar prediction market companies.
'This filing is representative of our bipartisan commitment to protecting state regulatory authority over illegal, unregulated gambling operations,' said Attorney General Bonta. 'Prediction markets cannot use federal loopholes to bypass state consumer protection, sports gaming, and gambling laws.
By joining this brief, we are standing firmly with Ohio and our state partners to ensure that federal commodities laws are not weaponized to evade state laws, fuel gambling addiction, and undermine state revenue.' The litigation stems from a lawsuit filed by Kalshi on October 7, 2025, claiming that federal law preempted Ohio's gaming regulations. On March 9, 2026, the U.S.
District Court for the Southern District of Ohio rejected Kalshi's arguments, ruling that the company's sports-event contracts are not 'swaps' under the Commodities Exchange Act, and that Ohio's gambling laws remain fully enforceable. Kalshi appealed the next day, and Ohio gaming authorities subsequently fined Kalshi $5 million for illegal gambling.
Two weeks ago, California joined a similar brief supporting Tennessee in a parallel case. The Sixth Circuit has consolidated the cases, with oral arguments scheduled for July 30, 2026.
Bonta joins attorneys general from Alabama, Alaska, Arizona, Arkansas, Colorado, Delaware, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Nebraska, New Jersey, New Mexico, New York, North Carolina, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Vermont, Virginia, Washington, Wisconsin, and Wyoming.