Polymarket on Monday sued Massachusetts’ attorney general to preempt the state from shutting down its sports prediction contract markets, following the state’s preliminary win barring Kalshi’s sports wagers.
The lawsuit, filed in the US District Court for the District of Massachusetts, presents the same line of defense that the emerging industry has presented to try to fend off state-level attacks, namely that the federal Commodity Futures Trading Commission’s oversight of Polymarket, Kalshi and other platforms preempts state efforts to regulate their activities.
Polymarket said the threat of enforcement is “immediate and concrete,” citing the Massachusetts action against Kalshi. A similar move against Polymarket would cause irreparable harm by disrupting its operations, “fragment” its national market, and make it “choose between exercising its federal right to operate nationwide or submitting to unlawful state coercion,” it said.
“Immediate judicial intervention is necessary to uphold Congress’ mandate, protect the federal market structure, and safeguard the rights of users nationwide,” Polymarket said in the complaint, which names Attorney General Andrea Campbell (D) and state gaming regulators as defendants.
Polymarket highlighted CFTC Chairman Michael S. Selig’s comments on Jan. 29 directing the commission to reassess how and whether it intervenes in litigation in cases testing its jurisdictional boundaries, which was followed last week with its filing of an amicus brief to the Ninth Circuit in a similar enforcement case involving Crypto.com.
The complaint comes on the heels of a Massachusetts state judge’s order last Friday declining to stay his preliminary ban on Kalshi’s sports event contracts after he ruled that the platform was subject to state gaming laws and required a license to offer sports contracts in the state. A federal judge Nevada, also Friday, denied Coinbase’s request for an order protecting it from an enforcement action filed by the state’s attorney general and gaming commission.
In the Massachusetts ruling, the state court judge said Kalshi’s reading of the CFTC’s regulatory powers was “overly broad” and he concluded that Congress didn’t intend the law to “displace traditional state police powers,” like gambling regulation. Kalshi promptly appealed the ruling and denied appellate stay.
Robinhood, which partners with Kalshi and another event prediction market, is also seeking a preliminary injunction in federal court in Massachusetts to block Campbell from forcing it to comply with the state’s sports gambling license regime.
In a statement on the lawsuit posted to social media networks, Polymarket Chief Legal Officer Neal Kumar said the company is fighting “for the users.”
He said gaming regulators’ “racing to state court to try to shut down Polymarket US and other prediction markets doesn’t change federal law,” adding that Massachusetts and Nevada will “miss an amazing opportunity to help build markets for tomorrow.”
A spokesman for the Massachusetts Gaming Commission declined to comment, and representatives for the attorney general weren’t immediately available for comment.
Polymarket is represented by Gibson Dunn & Crutcher LLP and Mintz Levin Cohn Ferris Glovsky & Popeo PC.
The case is QCX LLC v. Campbell, D. Mass., No. 1:26-cv-10651, complaint filed 2/9/26.
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