On March 27, 2026, Washington Attorney General Nick Brown filed a civil lawsuit against Kalshi in King County Superior Court, alleging the prediction-market platform violates the Washington State Gambling Act and Consumer Protection Act. The complaint joined a growing wave of state-level legal action against the platform — and notably went further than most filings by citing specific marketing concerns and revenue-mix data.

For New Mexico, the Washington complaint is relevant in three ways: it cites tribal-only sports betting as the existing legal regime that Kalshi circumvents, it includes detail about the percentage of Kalshi’s activity that is sports-related, and it documents concerning marketing practices toward college students.

What the complaint says

According to the Washington AG’s office and contemporaneous reporting by The Spokesman-Review and GeekWire:

“Kalshi operates in direct violation of [Washington’s] state laws that prohibit gambling, except for sports wagers placed on tribal lands.”

— Office of Attorney General Nick Brown

The complaint emphasizes that Washington has “some of the most restrictive gambling laws in the United States,” and that sports wagering in the state is reserved by law for tribal lands — the same structural feature that defines NM’s sports betting market. That parallel makes Washington’s argument particularly relevant to the federal lawsuit four NM tribes filed against Kalshi on May 12, 2026.

Two findings worth highlighting

Two findings in the Washington complaint stand out and have been cited widely in coverage of prediction-market litigation:

1. Sports is the business.

“More than 90% of the activity on Kalshi and 89% of its revenue last year was from sports betting.”

— Washington complaint, summarized by The Spokesman-Review

This data point cuts against Kalshi’s framing of itself as a general-purpose prediction market that happens to include sports. The Washington AG’s office argues the platform is functionally a sports betting operation that uses prediction-market structure to evade gambling regulation.

2. Marketing to college students.

“Kalshi has engaged in influencer campaigns targeting college students, even trying to recruit 15-year-old kids to promote gambling to their followers.”

— Washington complaint, as reported by GeekWire

This is a Consumer Protection Act claim distinct from the gambling-law violations. NM’s tribal complaint also cites the platform’s 18+ age policy as inconsistent with NM tribal sports betting’s 21+ minimum, but Washington’s filing adds a marketing-practice dimension.

Relief sought

Brown is seeking:

  • A preliminary injunction to stop Kalshi from operating in Washington immediately
  • Damages to be determined as the case develops, based on funds collected from Washington residents

The wider pattern in March 2026

Washington’s lawsuit came at a high-pressure moment for Kalshi. In the same week:

By the time NM tribes joined the fight in May, Kalshi was facing more than 20 civil lawsuits and concurrent criminal action in Arizona — even as the Third Circuit was ruling 2-1 in Kalshi’s favor on the federal preemption question.

Why the WA tribal-lands frame matters for NM

The most quoted line in the Washington complaint — that sports betting is “reserved for tribal lands” — is the structural mirror of NM’s regime. Both states (along with several others) allow sports betting only through tribal sportsbooks under compact agreements. Both arguments rest on the same point: a federally registered prediction market should not be allowed to do online what state law explicitly reserves for tribal operators.

If Washington wins on the merits, its decision becomes persuasive authority for NM and other tribal-exclusive states. If Washington loses on federal preemption grounds, NM’s tribal sovereignty argument under IGRA becomes one of the few remaining legal theories that could survive.

What it means for NM bettors

For now: nothing changes at NM sportsbook counters. The five legal NM books — Santa Ana Star, Isleta + BetMGM, Inn of the Mountain Gods, Buffalo Thunder, and Route 66 — continue to operate retail-only. Online sports betting in NM remains illegal. Kalshi continues to accept users from NM.