Detroit is set to become the first U.S. city to step into the court fight over prediction markets, after winning permission to file an amicus brief in support of Michigan’s position against Coinbase. A federal judge gave the city until April 3 to submit its brief in the case now moving through the Eastern District of Michigan.
The move adds a local government voice to a battle that has mostly been fought by state regulators, exchanges, and federal agencies. Coinbase sued Michigan in December, arguing that prediction markets fall under the Commodity Futures Trading Commission rather than state gambling law.
Detroit has a direct stake in how Michigan treats gaming competition
Detroit’s interest is not hard to understand. The city is home to Michigan’s three commercial casinos, and those properties reported $103.9 million in aggregate revenue in January and another $100.6 million in February. They also sent $12.3 million to the city in January through wagering taxes and development agreement payments.
That casino base gives Detroit a clear reason to watch any product that starts to look like betting while operating outside the state’s normal gaming system. The city has not yet filed its brief, so its full argument is not public, but its decision to join the case suggests it does not see the Coinbase dispute as a distant state-level issue.
The case adds another layer to Michigan’s prediction market fight
Michigan is already one of the busiest states in this legal clash. Coinbase’s case is one piece of a wider fight over whether sports and event contracts are federally regulated derivatives or gambling products that states can police themselves. That same question is sitting at the center of lawsuits involving Kalshi, Robinhood, and Polymarket in other jurisdictions.
Detroit’s entry does not change the core legal question, but it does change the shape of the fight. A state gambling case is now drawing in a city with real tax revenue and casino jobs on the line, which gives the Michigan side one more argument that prediction markets are not just a federal policy debate.
