Are Prediction Markets Legal in Washington?

Washington has the strictest interpretation of gambling law of any US state. Online gambling — including peer-to-peer poker — is a Class C felony under [RCW 9.46.240](https://app.leg.wa.gov/RCW/default.aspx?cite=9.46.240). Against that backdrop, Washington Attorney General Nick Brown filed a lawsuit on March 27, 2026 against Kalshi, alleging the platform "violates state law by operating and advertising an online platform" for illegal gambling. Robinhood has since countersued Washington in federal court, and the December 9, 2025 [Washington State Gambling Commission warning](https://wsgc.wa.gov/) declared that prediction markets are "not authorized" in Washington.

This is the most aggressive multi-front state action against prediction markets currently in progress in the United States. As of April 21, 2026, prediction-market platforms remain technically accessible to Washington addresses while the litigation runs, but the legal posture is the most uncertain of any major US prediction-market state.

Washington Prediction Market Timeline 2025–2026

• December 9, 2025 — Washington State Gambling Commission issues a public warning that "prediction markets are not authorized in Washington." Coverage in The Seattle Times treats this as the formal launch of WA enforcement.
• March 27, 2026 — AG Nick Brown files suit against Kalshi in King County Superior Court alleging violations of RCW 9.46. The Spokesman-Review and Seattle Times cover the filing. AG news release calls Kalshi's prediction-market framing "little more than a front for an illegal sports betting operation."
• April 3, 2026 — Robinhood files a federal countersuit against Washington state in the Western District of Washington, citing the December 2025 Gambling Commission warning and seeking declaratory relief that CFTC preemption applies. Coverage in KING-5 and Washington State Standard.
• April 21, 2026 — Both lawsuits remain active. Kalshi and Polymarket continue to accept Washington addresses while the Robinhood declaratory action proceeds.

Why Washington Is Uniquely Hostile

Three structural factors:

1. The country's broadest gambling statute. RCW 9.46 criminalizes essentially any online wagering not specifically authorized. Washington is one of only two states (Utah being the other) where any form of online gambling is a felony.
2. A powerful tribal gaming coalition. Washington has 29 federally recognized tribes operating tribal gaming under IGRA compacts. The Tulalip, Muckleshoot and Puyallup tribes have aggressively defended their gaming exclusivity. Sports betting in Washington is currently legal *only* on tribal lands (in-person), giving tribes effective monopoly control.
3. A consumer-protection-led AG. Nick Brown was elected on a consumer-protection platform. His office's news release on Kalshi emphasizes lack of state responsible-gaming protections and the 18+ age threshold.

What Washington Residents Can Trade Right Now

Despite the litigation, CFTC-regulated platforms have not pulled out of Washington. As of April 21, 2026:

• Kalshi: Operational. Full catalog including sports.
• Robinhood: Operational. Now actively suing the state to maintain access.
• Polymarket US: Operational, USDC↗-funded.
• OG.com: Operational.
• DraftKings Predictions / FanDuel Predicts / Fanatics Markets: Not available in Washington — these companies hold tribal-partnered sportsbook licenses elsewhere and have voluntarily geofenced their predictions products from WA.

Volume is meaningful but lower than peer states. Kalshi reports Washington as one of its top-15 states by user count, despite the litigation.

Best Prediction Market Platforms for Washington Residents

Kalshi — Primary target of AG Brown's lawsuit. Fully operational pending court ruling. Sports, politics, macro, crypto. CFTC Designated Contract Market.

Robinhood — Operational and now actively defending Washington access in federal court. Existing Robinhood brokerage users have access in-app. Zero commission.

Polymarket US — Available, USDC↗-funded, deepest crypto and political markets.

OG.com — Available, sports-focused, low fees.

DraftKings Predictions, FanDuel Predicts, Fanatics Markets — Not available in Washington (voluntary geofencing).

Novig, Chalkboard, Sleeper, Rebet — Not licensed in Washington.

Eligibility Checklist for Washington Residents

• 18+ on CFTC-regulated platforms.
• Government ID + SSN for KYC.
• Be aware that AG Brown's lawsuit, if successful, could result in platforms withdrawing from Washington with little notice. Avoid keeping unnecessarily large balances.
• Funding from a US bank account or debit card. Polymarket requires USDC↗.

Tax Treatment for Washington Residents

Washington has no state income tax, which is materially favorable for prediction-market traders compared to California (13.3%) or New York (10.9%). Federal treatment under IRC Section 1256 (60/40 capital gains split) applies. Consult a tax professional — the litigation creates additional complexity around how Washington might ultimately classify gains if the AG prevails.

What Happens Next

1. King County Superior Court ruling on AG Brown's lawsuit: Expected mid-2026. If WA wins, expect platforms to geofence WA within weeks.
2. Federal Western District of Washington ruling on Robinhood's countersuit: Expected late 2026. A pro-Robinhood ruling would bind WA to CFTC preemption.
3. Tribal intervention: Washington tribes are likely to file amicus briefs or independent suits — similar to the California tribal coalition.
4. Supreme Court↗ cert: The Robinhood vs. Washington case is one of the strongest candidates for Supreme Court review in 2027.

Sources

• Washington Attorney General: [Washington sues online betting platform Kalshi for illegal gambling](https://www.atg.wa.gov/news/news-releases/washington-sues-online-betting-platform-kalshi-illegal-gambling)
• Washington State Standard: [WA clashes in court with prediction market platforms Kalshi and Robinhood](https://washingtonstatestandard.com/2026/04/03/wa-clashes-in-court-with-prediction-market-platforms-kalshi-robinhood/)
• The Seattle Times: [Kalshi 'prediction market' violates WA antigambling laws, AG says](https://www.seattletimes.com/seattle-news/politics/kalshi-prediction-market-violates-wa-antigambling-laws-ag-says/)
• KING-5: [Robinhood sues Washington after state crackdown on Kalshi](https://www.king5.com/article/news/local/robinhood-sues-washington-after-state-crackdown-on-kalshi-prediction-markets)