Polymarket Takes Massachusetts Prediction Market Dispute to Court

The legal fight over prediction markets escalated in Massachusetts as Polymarket moved the dispute into federal court, challenging state level enforcement tied to sports related event contracts.

Good to Know

• Polymarket sued Massachusetts Attorney General Andrea Joy Campbell
• The case follows a setback for Kalshi in state court
• Federal oversight by the CFTC sits at the center of the dispute

Court filings landed only days after a Massachusetts judge rejected a bid from Kalshi to pause enforcement against its sports markets while an appeal proceeds. That ruling cleared the way for the state to continue actions against prediction market platforms operating within its borders.

Polymarket responded by filing suit against Andrea Joy Campbell, arguing that state officials lack authority over federally regulated event contracts. The lawsuit seeks to block enforcement of state gambling laws against the platform.

Neal Kumar, chief legal officer at Polymarket, addressed the move publicly after the filing saying:

“Congress gave the CFTC, not states, exclusive authority over event contracts. These are national markets with critical questions that must be resolved in federal court.”

The legal argument mirrors claims raised by Kalshi, which maintained that prediction markets fall under federal oversight by the Commodity Futures Trading Commission. Kalshi failed to secure a delay of the Massachusetts injunction while pursuing an appeal, a development that added urgency for other platforms.

In the complaint, Polymarket warned of immediate consequences if Massachusetts enforcement continues. The filing described “imminent and irreparable harm arising from Massachusetts enforcement of state gambling laws against federally regulated derivatives exchanges enforcement Congress has expressly prohibited.”

Polymarket pointed to the state early legal success against Kalshi as a sign of expanding risk. The platform labeled any state action against prediction markets as meritless enforcement that threatens the structure of federally approved markets.

According to the lawsuit, penalties or restrictions could fracture a national trading market, weaken liquidity, disrupt banking and commercial relationships, and erode user confidence. The filing argued that only federal courts can resolve disputes tied to nationally offered event contracts.

The platform emphasized urgency in its request for relief. It said:

“Immediate judicial intervention is necessary to uphold Congress mandate, protect the federal market structure, and safeguard the rights of users nationwide.”

Massachusetts marks the latest front in a growing series of state challenges. Polymarket recently exited Nevada after a court ruling favored the state position in a separate enforcement case. A judge upheld the lawsuit filed by Nevada, prompting the platform to vacate the market rather than continue operations under dispute.