Overview
Polymarket US’s exchange entity sued Michigan’s Attorney General and Gaming Control Board in March 2026 seeking to block enforcement against its sports event contracts. It lost twice. Judge Paul L. Maloney denied a temporary restraining order in March 2026 and then denied a preliminary injunction on June 17, 2026, in one of two near-identical opinions issued the same day (the other denying Robinhood Derivatives). Read from the opinion itself (ECF No. 41, 34 pp.), the holding has two independent parts. First, the statutory definition of “swap” is ambiguous, and Polymarket US’s products fall outside it: in one prong of a six-part definition of a single derivative type, enacted in a statute passed after the 2008 financial crisis, there is no clear statement that Congress meant to supersede the states’ traditional role in regulating gambling. Second, and independently, even if the products were swaps, the court held it is not clear the federal framework stops states regulating in what it called the porous zone where derivatives and gambling meet.
Polymarket US appealed the same day. In July 2026 the Sixth Circuit denied its motion to consolidate with the Kalshi appeals from Ohio and Tennessee, but ordered that this appeal and Robinhood’s be submitted to the same panel on the same day after briefing. The CFTC filed an amicus brief supporting Polymarket US in August 2026 — the agency backing a private platform against a state in a case it is not a party to.
In October 2026 Polymarket US joined Robinhood and Coinbase in standing down by agreement. A stipulated order entered October 27 ended new Michigan sports contracts and requires Michigan residents’ open sports positions to be closed by the end of November 25, with the State agreeing not to take enforcement action while it complies. The Gaming Control Board’s release says the Attorney General had warned Polymarket US on September 10 that she would sue if it did not stop. The appeal continues.
Timeline
March 2026
Polymarket US sues Michigan’s Attorney General and Gaming Control Board; the court denies a temporary restraining order.
June 2026
Judge Maloney denies a preliminary injunction; Polymarket US appeals to the Sixth Circuit the same day.
July 2026
The Sixth Circuit denies consolidation with the Kalshi appeals but orders this appeal submitted to the same panel, on the same day, as Robinhood’s.
August 2026
Opening brief filed; the CFTC files an amicus brief supporting Polymarket US; the district court stays proceedings pending appeal.
September 16, 2026
Michigan files its appellee brief.
September 25, 2026
The Sixth Circuit rejects the same preemption theory in Kalshi’s Ohio and Tennessee appeals, in a published opinion binding on this panel.
October 27, 2026
Stipulated order: Polymarket US stops offering new Michigan sports contracts and will close remaining open positions by the end of November 25, 2026; Michigan agrees not to take enforcement action while it complies.
What's next: On appeal at the Sixth Circuit (No. 26-1552), fully briefed but for Polymarket US’s reply. The panel is now bound by the court’s September 25, 2026 published decision against Kalshi, which held sports contracts are not shown to be swaps and that the CEA would not preempt Michigan-style gambling laws even if they were. It will be submitted with Robinhood’s appeal. The court sent the parties a letter on October 8 whose content is not on the public docket; no argument date or decision has been reported. Meanwhile Polymarket US has stood down in Michigan by agreement: under a stipulated order entered October 27, 2026, it stopped offering new Michigan sports contracts and must close Michigan residents’ remaining open sports positions by the end of the day on November 25, with the State agreeing not to take enforcement action while it complies. The stipulation’s full text is not on the free public record. November 25, 2026: Deadline for Polymarket US to close Michigan residents’ open sports positions
This page is informational, not legal advice. Nearly every entry in this tracker is a preliminary ruling under appeal. Always verify a platform's current, location-specific eligibility directly with the venue before relying on this page.