The National Football League filed an amicus brief with the US Supreme Court on Wednesday backing New Jersey's petition to determine whether prediction-market operator Kalshi falls under state or federal oversight. The filing tells justices that more than half of all prediction-market trading volume on the league's opening Sunday this season — $1.8 billion of $3.3 billion — flowed through NFL-linked contracts.

What does the league want SCOTUS to decide?

The NFL urged the high court to grant a writ of certiorari from New Jersey Attorney General Jennifer Davenport and interim gaming enforcement director Mary Jo Flaherty. Their September filing asks whether event contracts on Kalshi qualify as "swaps" supervised by the Commodity Futures Trading Commission or as sports wagers governed by state regulators.

The league argues that labeling NFL-linked contracts as swaps would strip away state-level integrity protections long embedded in US sports law. Federalizing sports-betting oversight would also raise a "major question" the justices should consider, the brief states.

How concentrated is the NFL's exposure?

Citing trading data, the NFL says $1.8 billion of the $3.3 billion in prediction-market activity on the first Sunday of the NFL season related to NFL events. That share — more than half of platform volumes — makes professional football uniquely exposed among regulated commodities, the league argues.

The filing calls NFL-related contracts "highly susceptible to manipulation" or "otherwise inherently objectionable." It warns that the CFTC's framework lacks the integrity safeguards that state regulators enforce in licensed sports books. A single actor with advance notice of a trade can move betting lines, the league notes.

"These bets, in the NFL's view, pose the greatest threats to game integrity, because many can be manipulated by a single person, especially if known in advance — for instance, a player can alter his performance, a coach can change his team's lineup, or an official can make (or not make) certain calls," the brief states.

What is the broader state-federal fight?

Thirty-nine US states and the District of Columbia filed a separate amicus brief on Wednesday backing New Jersey. They frame the dispute as a "national turf war" between the CFTC and state gaming regulators that cannot be resolved without Supreme Court intervention.

"Waiting too long to address this issue will permit the federal-state regulatory dispute to escalate," the multistate filing states. "The ongoing power struggle between the States and the CFTC highlights the unpredictability about what law applies — and to whom."

Kalshi has pushed back on the patchwork. Spokesperson Dani Lever said in September that the firm "could not be regulated by 50 different regulators" — an argument the company is expected to sharpen in its Supreme Court response.

What happens next?

Kalshi secured an extension to respond to New Jersey's petition until November 9, with submissions set to address jurisdiction, manipulable event contracts and consumer protection. The court had not announced by Thursday whether it would take the case.

If SCOTUS grants review, the resulting ruling would resolve multiple state enforcement actions already in flight against Kalshi and rivals including Polymarket, which faces a New York lawsuit over alleged illegal gambling activity. A denial would leave circuit splits in place, allowing the CFTC to continue treating sports event contracts as swaps while state cases proceed on parallel tracks.