Polymarket to stop sports contracts in Michigan after MGCB deal, with existing contracts to close out by Nov. 25

Polymarket US has agreed to end new sports-event trading for Michigan customers under a deal with the Michigan Gaming Control Board (MGCB), according to The Lines’ Oct. 30, 2026, report. Existing contracts must be resolved and closed out by Nov. 25.

The agreement adds Polymarket to the exchanges withdrawing sports contracts from Michigan, where regulators consider the products unlicensed sports betting. It does not settle the broader dispute over whether federal oversight shields prediction markets from state gambling laws.

Michigan’s enforcement campaign

Michigan Attorney General Dana Nessel sued Kalshi in March 2026, alleging violations of the Lawful Sports Betting Act (LSBA). The state has had regulated online sports betting since 2019. According to The Lines, a Michigan judge issued a temporary restraining order against Kalshi’s sports contracts in June 2026; in July 2026, the Commodity Futures Trading Commission (CFTC) directed Kalshi to honor outstanding contracts.

Robinhood and Coinbase have also halted sports contracts in Michigan, The Lines reports. Its account gives inconsistent timing for those withdrawals, but identifies both as preceding Polymarket’s agreement. In September 2026, the state attorney general warned Polymarket of legal action unless it stopped offering sports contracts.

Court challenges remain unresolved

Polymarket US sued Michigan officials in federal court in March 2026 to head off state gambling enforcement. The court rejected its request for a temporary restraining order, and its appeal remains pending in the Sixth Circuit, according to The Lines. The agreement therefore comes alongside an unresolved legal challenge.

Prediction markets maintain that they operate under federal CFTC regulation rather than as sportsbooks. Court outcomes have differed: The Lines reports that the Ninth Circuit Court of Appeals recently upheld Nevada’s authority to regulate sports-related contracts in its dispute with Kalshi, while the Third Circuit U.S. Court of Appeals ruled against New Jersey in April. The outlet identifies a possible U.S. Supreme Court confrontation as early as next summer, though such a review is not assured.

What it means for prediction markets

• Michigan access is narrowing: Polymarket’s agreement ends new sports-event trades in the state and sets Nov. 25 as the deadline for resolving and closing existing contracts.
• The withdrawal is not a final legal ruling: Polymarket’s Sixth Circuit appeal remains pending, leaving its underlying challenge unresolved.
• Availability remains state-dependent: The Michigan agreement does not establish a nationwide prohibition. Divergent court decisions continue to leave sports-contract access dependent on jurisdiction.
• Supreme Court timing remains uncertain: A potential review is a legal development to monitor, not a confirmed event or timetable.