Washington sues online betting platform Kalshi for illegal gambling

Attorney General Nick Brown filed a lawsuit today against Kalshi, a company that violates state law by operating and advertising an online platform where users can bet on sports, elections, and other events. Kalshi even allows consumers to bet on the total number of "measles cases this year," "what will witnesses say" during a child trafficking hearing, or potential outcomes in the Iran war.

Kalshi attempts to skirt state law by branding its betting platform as a "prediction market," but whatever Kalshi chooses to call it, Kalshi's operations clearly fall under the definition of illegal gambling in Washington. The lawsuit argues Kalshi violates the Washington state Gambling Act and Consumer Protection Act, and seeks to halt these unlawful activities, recover money lost by Washingtonians, and assess civil penalties.

"Kalshi wants people betting on almost everything possible in life-the outcome of elections, Supreme Court cases, even wars. For Kalshi, every event, every tragedy is nothing more than a potential way for Americans to risk their fortunes and for Kalshi to get rich," said Brown. "As they advance this bleak vision of the future, they line their pockets and pat themselves on the back for sneaking around Washington's gambling laws. No more."

The definition of gambling under Washington law is "staking or risking something of value upon the outcome of a contest of chance or a future contingent event," and Kalshi's activities fall squarely within that definition. Each Kalshi bet risks money, relies in part on chance, and promises a payout to winners.

Kalshi's website and app show consumers a range of events that they can bet on and the odds for those various events, which dictate how much the bettor will be paid out if the event occurs. This is exactly how sportsbooks and other gambling operations function. Kalshi advertises that they allow consumers to "bet on anything" by simply calling their service a "prediction market" rather than "gambling." In one Kalshi advertisement, one person texts another that they "found a way to bet on the NFL even though we live in Washington," which seems to acknowledge that Kalshi knows that they are attempting to skirt state law. In fact, Kalshi did find a way to bet on the NFL in Washington; all they had to do was break the law.

Kalshi entered the betting market in 2025, first allowing Washington consumers to bet on both college and pro sports. Kalshi offers spread bets (a bet on the difference in score between two competing sports teams), over/under bets (a bet on how many total points will be scored in a sports game), and proposition bets (bets on specific events that may occur within a sports game, such as the number of touchdowns a football player might score during the game). All of these types of bets are commonly offered by sportsbooks and casinos, and unlawful in Washington state. Its activities spread quickly, encompassing all ranges of betting.

From the beginning, when Washington became a state in 1889, its constitution prohibited gambling on state lands, and the state continues to carefully regulate gambling activities to protect and safeguard the public since then. In 2006, the Legislature amended the 1973 Gambling Act to make it clear that internet gambling is prohibited under Washington law. But online platforms like Kalshi put consumers at particular risk for problem gambling.

Kalshi has marketed itself to young people between the ages of 18 and 21. They have coaxed college students to their platform, advertising that "College campuses…will play a key role in bringing the next 100M users" to their product. They routinely pay college student influencers to promote their gambling app to their peers, and at one point event briefly tried to recruit a 15-year-old influencer to promote their brand.

Read the complaint here.

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If you or someone you know is suffering from gambling addiction or gaming disorder, please contact the Washington State Problem Gambling Helpline at 1-800-547-6133. Other resources can also be accessed here.

Consumers wanting to file a complaint with the Consumer Protection Division should call 1-800-551-4636 or 1-800-833-6384 for the hearing impaired or visit the AG web site at https://www.atg.wa.gov/file-complaint.