The Ho-Chunk Nation has filed a federal lawsuit against Kalshi, an online prediction market, arguing that the company is running an illegal sports-betting business that violates state, federal, and tribal law.

     The case, filed last month in U.S. District Court, centers on Kalshi’s platform, which lets users wager money on the outcome of real-world events through an app and website accessible nationwide, including within Ho-Chunk tribal lands.

     While Kalshi markets itself as a regulated financial exchange, the Ho-Chunk Nation officials say the system is nothing more than unlicensed sports gambling that siphons revenue from tribal casinos.

     In Wisconsin, sports betting is tightly restricted. Under state compacts, only tribal nations may operate sports books, and only within their casinos.

     The Ho-Chunk Nation operates several gaming facilities across the state and argues that Kalshi’s activities directly cut into tribal revenues.

     The lawsuit also highlights what the Nation calls deceptive advertising, pointing to Kalshi’s promotional claims that it is the “first nationwide legal sports betting platform” and that “sports betting [is] legal in all 50 states.”

     App store descriptions and posts from the company’s leadership on TikTok are also cited as evidence that Kalshi is intentionally presenting itself as a sportsbook.

     The Wisconsin case follows a similar suit brought by three California tribes earlier this summer, also targeting Kalshi for alleged illegal gambling. Both cases are being handled in part by the law firm Rapport and Marston, alongside Quarles and Brady in the Ho-Chunk Nation’s filing.

     The complaint seeks both financial damages and an injunction that would bar Kalshi from operating on or near Ho-Chunk lands.

     Tribal leaders argue that every dollar diverted from their casinos through unregulated wagering undermines their ability to fund essential services and programs for citizens and residents on tribal lands.

     Kalshi, launched in 2021, lets users buy and sell contracts on yes-or-no outcomes, whether it’s a sports game, a political race, or even the weather. The company expanded into sports event contracts in early 2025 after filing a self-certification with regulators.

     The platform has partnered with Robinhood Markets Inc., which was also named in the lawsuit. Robinhood maintains that Kalshi’s products are not gambling but rather futures contracts regulated by the Commodity Futures Trading Commission (CFTC).

     The firm says the so-called “event contracts” offer retail customers access to prediction markets in a safe, compliant manner.

     Kalshi representatives have not publicly commented on the Wisconsin lawsuit. However, in recent months the company has continued to promote its offerings as innovative financial products.