38 attorneys general back Massachusetts suit against Kalshi

Thirty-eight state attorneys general filed an amicus brief with the Supreme Judicial Court of Massachusetts supporting a lawsuit that accuses Kalshi of offering unlicensed sports betting through so-called event contracts.

The coalition asks the court to enforce state gambling rules and to bar Kalshi from allowing Massachusetts residents to place sports wagers without a state license while the case proceeds.

Massachusetts filed the original complaint in September 2025, saying Kalshi’s contracts let users wager on the outcomes of sporting events without meeting state licensing and consumer-protection requirements. The brief submitted by the coalition repeats those claims and asks the court to uphold a lower-court order that temporarily restricts Kalshi’s sports-related activity for Massachusetts residents unless the company obtains the required license.

Signatories include attorneys general from California, New York, New Jersey, Nevada and Pennsylvania, among others. New York Attorney General Letitia James wrote that “Prediction markets cannot ignore states’ gambling laws that are designed to protect consumers,” and described Kalshi’s sports contracts as “just illegal gambling by another name.”

The attorneys general argue the Dodd-Frank Wall Street Reform and Consumer Protection Act does not remove states’ authority over gambling. Their brief says Dodd-Frank targeted financial instruments tied to the 2008 financial crisis, does not mention gambling and does not clearly displace traditional state control of betting. The filing notes that when Dodd-Frank was enacted, federal law effectively barred states from legalizing sports betting until a 2018 Supreme Court decision changed that legal landscape.

Massachusetts’ filing cites trading volume on Kalshi’s platform, saying users wagered more than $1 billion per month in 2025 and that roughly 90% of that volume was tied to sports outcomes.

Kalshi disputes the allegations, saying its event contracts are financial swaps regulated by the Commodity Futures Trading Commission and therefore fall under federal jurisdiction. The CFTC filed an amicus brief on April 24 asserting exclusive authority over prediction markets. CFTC Chairman Michael S. Selig wrote that “Congress has entrusted the CFTC with the sole authority to regulate commodity derivatives markets, including prediction markets.”

The court’s decision will determine whether states can apply their gambling licensing schemes to online event contracts or whether federal law and CFTC oversight preempt state enforcement. The case centers on how courts interpret the scope of Dodd-Frank and the CFTC’s authority in relation to state gambling regulation.