Prediction Market Lawsuit Tracker: 49 Cases, Checked Against the Court Record

The Supreme Court's October Term opens on 5 October 2026 with three petitions on its docket asking whether federal law pre-empts state gambling law for sports event contracts. Robinhood's, from the Ninth Circuit's ruling for Nevada, has a response due on 14 October; Crypto.com's on 15 October; New Jersey's, from the Third Circuit's ruling for Kalshi, on 9 November after an extension. Below them, the Fourth Circuit has yet to rule on Maryland's case, argued on 7 May, and a Second Circuit panel is hearing Kalshi's injunction motions in the New York and Connecticut appeals together.

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The appeals courts are split. The Third Circuit held on 6 April 2026 that Kalshi is likely to show the Commodity Exchange Act pre-empts New Jersey's gambling laws for its sports event contracts. The Ninth Circuit, on 28 August, and the Sixth, on 25 September, sided with the states: neither accepted that the contracts are swaps under the CFTC's exclusive jurisdiction, which would have put them beyond the reach of state gaming law. Each ruling is on preliminary relief, and three petitions ask the Supreme Court to settle the question.

Below the appeals courts, the federal government has taken the venues' side. The United States and the CFTC have sued eight states, and the district courts have gone both ways: injunctions in Arizona on 5 May and Minnesota on 27 July, a refusal in Wisconsin on 28 July. States and cities have brought cases of their own against Kalshi and Polymarket US, the newest being New York's on 24 September; tribes have sued over contracts entered on their land; users have brought class actions against both venues; and two traders have been charged with insider trading on Polymarket's international venue.

What the cases mean for each venue and state is set out in Is Polymarket legal in the US?; Is Polymarket just sports betting? measures how much of the trading they concern.

Three petitions ask the Supreme Court whether federal law pre-empts state gambling law for sports event contracts traded on CFTC-registered markets. Two come from the Ninth Circuit's rulings for Nevada and one from the Third Circuit's ruling against New Jersey.

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The Third Circuit ruled for the exchange in New Jersey on 6 April 2026. The Ninth Circuit ruled for Nevada in three appeals decided on 28 August, and the Sixth for Ohio and Tennessee on 25 September. All five rulings are on preliminary relief.

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Since 2 April 2026 the United States and the CFTC have sued eight states to stop them applying gambling law to exchanges the CFTC regulates. Judges granted injunctions in Arizona and Minnesota and refused one in Wisconsin.

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Exchanges have sued state officials to stop enforcement. Courts in Connecticut, New York, Maryland and Michigan refused them preliminary injunctions, and those appeals are pending.

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States and cities have sued Kalshi, Polymarket and other venues, mostly in state court; most cases were removed to federal court, and several have been sent back. Washington and Massachusetts won preliminary injunctions against Kalshi, and Nevada won a restraining order against Polymarket.

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Tribes in California, Wisconsin and New Mexico argue that sports contracts entered on their land violate the Indian Gaming Regulatory Act. The Ninth Circuit held that the California tribes are likely to win.

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Users have brought class actions against Kalshi and Polymarket, mostly over unlicensed sports betting, and the venues want them sent to arbitration. The Mexican football federation has sued Kalshi over its trademarks.

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Two traders have been charged with insider trading on polymarket.com, each in a criminal case with a parallel CFTC complaint in Manhattan. How an insider screen treats their trading is in Polymarket insider trading: the charged cases.

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Checked on 27 September 2026. Each case was read against the court's own opinion, order, complaint or petition where one could be opened (35 cases), against the docket index alone where the filing is not public (4), or in part (10), and each row says which. Quoted holdings were checked against the saved text of their documents.

Dockets come from the Supreme Court's site, the appeals courts' opinion pages, the CFTC's filings and CourtListener's copy of the federal courts' records, which can lag the court. Federal appellate dockets and state dockets behind a login were not read, so the latest entry is the latest seen, not a guarantee that nothing has happened since. Several court sites block automated reading.

The list is a selection of the cases that decide where sports event contracts may be offered, not a census. Cases seen only in search listings or described only in another party's filing are left out until a document or docket can be opened. Complaints and petitions are allegations, and most rulings listed are on preliminary relief, not final judgments. All 49 rows as a CSV.