In December 2025, Connecticut tribes filed an amicus brief against Kalshi. They say the prediction market diverts casino revenue from tribal lands.
State regulators had issued cease-and-desist orders to halt unlicensed online gambling. The notice told Kalshi, Robinhood, and Crypto.com to stop sports event contracts and allow withdrawals.
In December 2025, Kalshi sued the Connecticut Department of Consumer Protection. Kalshi said the regulator was “threatening Kalshi with imminent criminal and civil penalties for offering [event contracts].”
The Indian Gaming Association and 16 federally recognized tribes joined the amicus brief. They said “Congress gave it permission to enter Indian lands and siphon gaming revenues away from tribes over such tribes’ objections.”
Both the Connecticut brief and a California lawsuit argued that offering sports-linked contracts on tribal lands violates the Indian Gaming Regulatory Act. Data shows prediction markets reached about $6 billion in weekly volume, with Kalshi valued near $11 billion after a $1 billion raise and Polymarket valued near $9 billion after a $2 billion investment from Intercontinental Exchange.
