A contract pricing whether the Court grants certiorari has moved from 29% to 52% since a Ninth Circuit ruling, with three parties seeking review through different procedural routes.
The litigation defining whether federally regulated prediction markets can offer sports-event contracts has reached the Supreme Court's docket from three directions, and a market now exists to price whether the Court will take it.
Following an August 28 Ninth Circuit panel ruling, Kalshi filed for rehearing en banc. Robinhood filed a petition for certiorari with the Supreme Court on September 9. The State of New Jersey filed its own certiorari petition on September 2.
A Polymarket contract prices the probability that the Supreme Court accepts the case at 52%, up from 29% before the Ninth Circuit ruling. A separate contract prices acceptance specifically before October 31 at 6%. Combined trading volume approaches $1 million.
What the pricing actually represents
These figures are market-implied probabilities of a discretionary procedural decision, not predictions of the merits. Whether the Court grants certiorari and whether Kalshi's sports contracts are ultimately lawful are separate questions, and the contract addresses only the first. The 52% level says traders think the Court is more likely than not to hear the case. It says nothing about who wins.
The move from 29% to 52% is the more informative number. It is a roughly 23-point repricing driven by an identifiable event, the Ninth Circuit panel ruling, and it reflects the standard logic of certiorari: the Court takes cases where circuit courts have split or where an important federal question is unsettled. A panel ruling that sharpens a disagreement raises the odds of review more than the ruling's direction does.
The 6% probability of acceptance before October 31 is the practical calibration. Traders expect the Court to take the case eventually, and do not expect it soon. That combination is consistent with how certiorari petitions actually move, and it means the operative timeline is measured in months.
Three petitions, three different interests
That Robinhood, New Jersey and Kalshi are all seeking review, through different procedural vehicles, is itself a structural signal. A brokerage, a state regulator and an exchange do not share an objective. What they share is an interest in resolution, because the current condition, in which the legality of a product category depends on which circuit a dispute lands in, is unworkable for every participant regardless of which way it eventually breaks.
For the industry, that uncertainty is the binding constraint on capital deployment and product expansion, more than any single ruling would be.
A market pricing its own regulatory future
There is a recursive quality worth noting. The instrument pricing this litigation exists on a platform whose own regulatory standing is adjacent to what the litigation decides. That does not invalidate the price; it does mean participants are unusually well informed about the subject and unusually exposed to the outcome.
The next dated events are the Ninth Circuit's disposition of Kalshi's en banc petition and the Supreme Court's response to the two certiorari petitions. Neither has a confirmed date.