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Is Polymarket legal in Missouri?

Status as of September 25, 2026 · every line has its source and date · not legal advice

Status at a glance

Kalshi and Polymarket US are reported live in Missouri, including sports, but the Attorney General sent both cease-and-desist letters dated 2026-09-16 with a 30-day response window (about 2026-10-16) and said failure to comply will result in enforcement action.

What has happened in Missouri

Good to know

• Legal sports wagering launched in Missouri at 12:00 a.m. on Dec. 1, 2025, after voters approved Amendment 2 on Nov. 5, 2024; patrons must be at least 21 and physically in Missouri to place a wager. Missouri Gaming Commission Announces Official Launch of Sports Wagering
• The Attorney General's letter says Missouri bars sports wagering by anyone under 21, while Kalshi's Member Agreement allows anyone who has reached the age of majority, which is 18 in Missouri. Missouri Attorney General letter to KalshiEX LLC: Unlicensed Sport Wagering Operations in Missouri
• The Attorney General's letter says Polymarket's US Rulebook allows users aged 18 and older, while Missouri bars sports wagering by anyone under 21. Missouri Attorney General letter to QCX Limited Liability Company (Polymarket): Unlicensed Sport Wagering Operations in Missouri
• The letters ask for a response within 30 days of their Sept. 16, 2026 date, which is about Oct. 16, 2026, and say Missouri will take legal action if the companies neither comply nor stop. Missouri Attorney General letter to KalshiEX LLC: Unlicensed Sport Wagering Operations in Missouri
• No lawsuit by Missouri against Kalshi or Polymarket was found as of 2026-09-25; the check covered the Attorney General's press-release index and its uploaded documents. Missouri Attorney General - Press Releases
• The letters say Missouri 'remains open to possible legislative reforms in the future', and no 2026 Missouri House bill title mentions prediction markets or event contracts; bill texts and Senate bills were not searched. Missouri House of Representatives - Bill List, 2026 Regular Session
• Fox Sports' state table lists Missouri's prediction-market status as 'Available.' Where Are Prediction Markets Legal? State-by-State Availability in 2026 (FOX Sports) (news)

State regulator: Missouri Gaming Commission. Licenses and regulates sports wagering, which launched Dec. 1, 2025; the September 2026 cease-and-desist letters came from the Missouri Attorney General, not the Commission.

The federal picture

Polymarket US operates as a CFTC-designated contract market after Polymarket bought the CFTC-licensed exchange QCEX; Kalshi has been a designated contract market since 2020. Whether states may still apply their gambling laws to sports event contracts is being decided in the courts:

• 2026-09-25 Pending appellate decisions that could change several states' status: Sixth Circuit (Kalshi v. Ohio, No. 26-3196, and Kalshi v. Tennessee, No. 26-5235; argued 2026-07-30), Fourth Circuit (Kalshi v. Maryland, No. 25-1892; argued 2026-05-07), Second Circuit (Kalshi's New York and Connecticut appeals, Nos. 26-1835 and 26-2239, heard in tandem), Seventh Circuit (CFTC and Kalshi appeals from the Wisconsin injunction denial, No. 26-2636 et al.), Tenth Circuit (Kalshi v. Utah, No. 26-4100). No decision in any of these appeared in the court records checked for this file (CourtListener; indexes can lag PACER by a few days). CourtListener dockets cited in the Ohio, Tennessee, Maryland, New York, Connecticut, Wisconsin and Utah entries
• 2026-09-16 Ninth Circuit (Blue Lake Rancheria v. Kalshi, Inc., No. 25-7504; Murguia, McKeown, Paez; opinion by Judge McKeown) affirmed in part and reversed in part the denial of two California tribes' preliminary-injunction motion, holding the tribes likely to succeed in showing Kalshi's sports event contracts entered from tribal lands are class III gaming offered in violation of IGRA and their gaming procedures; the case was remanded for the remaining injunction factors, so no injunction had issued as of the last docket entry checked. Blue Lake Rancheria v. Kalshi, Inc., No. 25-7504 (9th Cir. Sept. 16, 2026) - published opinion (PDF)
• 2026-09-09 Kalshi petitioned for panel rehearing and rehearing en banc of the Ninth Circuit's 2026-08-28 Nevada decision (KalshiEX, LLC v. Assad, No. 25-7516); Montana's 2026-09-17 enforcement pause is tied to the outcome of that request. KalshiEX, LLC v. Assad, No. 25-7516 (9th Cir.) docket, entry 206 (CourtListener); Joint Stipulation of Dismissal, KalshiEX LLC v. Knudsen (D. Mont.), Doc. 35
• 2026-09-02 New Jersey petitioned the US Supreme Court for certiorari in Flaherty v. KalshiEX, LLC (No. 26-299, docketed 2026-09-08); Kalshi's response deadline was extended to 2026-11-09; an amicus brief was filed 2026-09-22 by the National Council of Legislators from Gaming States. Supreme Court docket No. 26-299
• 2026-08-28 Ninth Circuit (KalshiEX, LLC v. Assad, No. 25-7516; opinion by Judge R. Nelson, with Judges Bade and Lee; Lee concurring) affirmed in part the District of Nevada's order dissolving Kalshi's preliminary injunction, holding the CEA likely does not preempt Nevada gaming law as applied to Kalshi's sports event contracts (which it described as sports bets, not 'swaps'), and remanded for the district court to consider Nevada's challenges to Kalshi's election contracts. Nevada's regulator described the ruling as a 3-0 decision also covering Crypto.com and Robinhood. KalshiEX, LLC v. Assad, No. 25-7516 (9th Cir. Aug. 28, 2026) - published opinion (PDF)

How sure is this page? Confidence: high. The Missouri Attorney General's own Sept. 16-18, 2026 letters and release, plus a Sept. 24, 2026 CBS Sports roundup, confirm current availability and the only state action, though the status could change after the 30-day response window. Researched September 25, 2026; court cases in several states can change the status at any time.

Related: all states · Polymarket US · polymarket.com and the United States · is Kalshi legal in Missouri? (Kalshi View)

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Frequently asked questions

Is Polymarket legal in Missouri?

As of September 25, 2026: polymarket.com does not let US users open new positions, including in Missouri. Polymarket US, the CFTC-regulated app, is reported available in Missouri according to Missouri Attorney General letter to QCX Limited Liability Company (Polymarket) (September 16, 2026). 2 state actions involving Polymarket and 2 involving Kalshi are listed below with their sources. This is a dated summary of public sources, not legal advice.

Can I use polymarket.com from Missouri?

Not for new trades. Polymarket's help center lists the United States as a blocked country and its developer documentation lists it as close-only (existing positions can be closed, new ones cannot be opened); US residents are pointed to Polymarket US.

Is Kalshi available in Missouri?

Available; sports contracts available, according to the sources on this page as of September 25, 2026.

Polymarket View is independent and not affiliated with Polymarket or Kalshi. This page summarises public sources; it is not legal advice. Polymarket odds today