The National Football League (NFL) has largely sided with New Jersey officials in their petition asking the US Supreme Court to hear a case that could determine whether sports bets on prediction market platforms fall under state or federal jurisdiction.

In an amicus brief filed with the Supreme Court on Wednesday, the NFL urged the justices to grant a petition for a writ of certiorari from New Jersey Attorney General Jennifer Davenport and gaming enforcement interim director Mary Jo Flaherty. Amicus briefs allow non-parties to a case to weigh in on the questions presented, while a writ of certiorari is the discretionary mechanism through which the justices agree to hear a dispute. The state officials are seeking review of their case against Kalshi, a move that could settle whether prediction market companies answer to state authorities or federal agencies.

The league endorsed many of New Jersey's core arguments, including concerns over labeling sporting-event contracts on prediction market platforms as “swaps,” and argued that review is needed to “preserve game integrity” and “protect customers.” Citing trading data, the NFL said that on the first Sunday of the football season, “more than half of all prediction-markets’ trading volume” — roughly $1.8 billion of $3.3 billion — was tied to the NFL, a share that illustrates how much of these platforms' activity revolves around sporting outcomes.

According to the filing, many sporting event contracts on Kalshi and similar platforms were “highly susceptible to manipulation” or “otherwise inherently objectionable,” including markets such as Kalshi's event contract on the 2027 Super Bowl.

“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 amicus brief said.

The league also flagged the absence of what it called “sensible safeguards” for event contracts from the Commodity Futures Trading Commission (CFTC), and said that federalizing sports betting regulation, rather than leaving it to individual US state authorities, is a “major question” the Supreme Court should consider. The CFTC is the federal regulator of the US derivatives markets, the framework under which prediction market platforms have operated — and the federal role state officials are now contesting for sports-related contracts.

As of Thursday, the Supreme Court had not announced whether it would grant review. Kalshi was granted an extension to respond to the New Jersey filing, giving the company until Nov. 9 to address issues related to jurisdiction, manipulable event contracts, and consumer protection.

States urge the Supreme Court to step in

Also on Wednesday, 39 US states and the District of Columbia filed an amicus brief supporting New Jersey's position, arguing that the conflict between the CFTC and state authorities over prediction markets has produced a “national turf war” that cannot be resolved without an answer from the Supreme Court. A circuit split — conflicting rulings among federal appeals courts — is among the clearest signals the justices look for when deciding whether to intervene.

“Waiting too long to address this issue will permit the federal-state regulatory dispute to escalate,” the filing said. “The ongoing power struggle between the States and the CFTC highlights the unpredictability about what law applies—and to whom. Whether in this case, or in one of the many more cases sure to come, this Court should step in, resolve the circuit split, provide guidance to lower courts, clarify the CFTC's authority, and provide the badly needed answer to the Question Presented.”

Kalshi spokesperson Dani Lever told Cointelegraph after New Jersey's September filing that the company could not be “regulated by 50 different regulators.”

It remains unclear whether the Supreme Court justices will take up the issue of prediction markets. While New Jersey officials were the first to petition the high court over the Kalshi case, a wave of state-level actions against prediction market companies could still face appeal, including New York's lawsuit against Polymarket over an alleged illegal gambling business. Kalshi's Nov. 9 response and the justices' decision on whether to grant review now stand as the case's next procedural milestones.

Source: Cointelegraph