Kalshi secures exclusive US Open prediction market partnership

Kalshi has secured an exclusive partnership with the U.S. Tennis Association to become the US Open’s prediction market platform partner as the tournament’s main draw gets underway in New York.

Front Office Sports reported on Aug. 30, citing two people familiar with the agreement, that the partnership took effect immediately after being finalized following last week’s qualifying rounds. Financial terms and other parameters of the agreement were not disclosed.

The deal gives Kalshi an official role at one of tennis’s four Grand Slam tournaments and was completed later than initially planned. The US Open, owned and operated by the USTA, had previously considered waiting until 2027 or later before entering a prediction market partnership.

Kalshi becomes US Open prediction market partner

Discussions in recent weeks had involved multiple prediction market platforms and focused partly on match integrity and potential partnerships beginning next year, Front Office Sports reported.

Plans changed after Craig Tiley took over as USTA CEO on July 20. Tiley played a major role in pushing for an agreement covering the 2026 tournament, according to the report.

One source told Front Office Sports that the arrangement would prevent competing prediction market companies from advertising at the US Open venue and across television coverage of the tournament, including ESPN broadcasts.

The agreement had not yet been fully reflected across the organizations’ public materials when the main draw started Sunday. Kalshi was absent from the US Open’s official partner list as of Sunday afternoon.

A Kalshi blog post published earlier that day analyzing the women’s singles tournament still carried a disclaimer saying the company was “not affiliated with the U.S. Open or WTA,” according to Front Office Sports.

Kalshi already offers a large number of contracts tied to US Open matches. Its tennis markets on Sunday included individual men’s and women’s singles matches, with some contracts recording more than $1 million in trading volume.

The US Open agreement expands a sports strategy that has increasingly put prediction market platforms alongside leagues, teams and major events.

In June, crypto.news previously reported that Kalshi had secured World Cup branding exposure through a partnership with ADI Predictstreet, FIFA’s official prediction market partner for the 2026 tournament. The arrangement placed Kalshi branding alongside ADI Predictstreet across stadium, television and digital coverage beginning with the knockout stage.

Sports partnerships have spread across the prediction market industry. Kalshi and Polymarket have partnerships with the NHL, while Polymarket has worked with Major League Baseball and the New York Yankees. Kalshi has separately announced relationships with MLB clubs including the Atlanta Braves, Boston Red Sox, Los Angeles Dodgers, San Diego Padres and San Francisco Giants.

Novig has moved into the same market through a partnership with the New York Mets, becoming the first prediction market platform to sign an individual MLB team.

Sports contracts drive Kalshi’s expansion

Sports have become a central source of trading activity for Kalshi as the platform expands beyond the political and economic event contracts that helped prediction markets gain attention.

The company’s sports strategy was particularly visible during the FIFA World Cup. Weekly Kalshi trading volume reached a record $5.1 billion in June as activity tied to the tournament increased, while sports-related contracts had become its largest product category, according to previous coverage.

Kalshi has developed compliance systems alongside the expansion. Its sports-market surveillance includes IC360 screening and a prohibited-persons system designed to identify athletes, coaches, referees and league personnel who should not trade certain contracts. The company has paired those controls with its proprietary Poirot detection engine and Solidus Labs’ HALO surveillance platform, as detailed in crypto.news’ examination of prediction market surveillance in July.

The commercial push has continued while courts consider whether sports event contracts offered on federally regulated prediction markets can remain outside state gambling regimes.

Kalshi faces conflicting rulings over sports contracts

Two days before the US Open partnership emerged, Kalshi suffered a setback in its dispute with Nevada gaming regulators.

The Ninth U.S. Circuit Court of Appeals ruled on Aug. 28 that Kalshi had not shown that the Commodity Exchange Act was likely to preempt Nevada gaming regulations as applied to its sports event contracts. The three-judge panel affirmed in part a lower court order dissolving a preliminary injunction that had prevented Nevada from enforcing its laws against Kalshi.

Nevada’s Gaming Control Board had sent Kalshi a cease-and-desist letter alleging that it was operating a sports betting platform in violation of state laws and gaming regulations.

Kalshi argued that it operates as a designated contract market under the Commodity Exchange Act and that the Commodity Futures Trading Commission therefore has exclusive authority over its sports contracts.

The Ninth Circuit rejected Kalshi’s request for preliminary protection from Nevada enforcement. Its ruling found that the sports event contracts at issue did not qualify as swaps under the relevant Commodity Exchange Act definition because they were sports bets. The court remanded issues involving Kalshi’s election contracts to the district court for further consideration.

The decision came after Kalshi and Polymarket had already lost separate efforts connected with state gambling enforcement. In May, a Ninth Circuit panel denied emergency motions involving disputes in Nevada and Washington, finding that a Commodity Exchange Act preemption defense did not by itself establish federal jurisdiction.

Kalshi received a different result in the Third Circuit, which previously upheld preliminary relief preventing New Jersey regulators from enforcing state gambling laws against its sports contracts. The court found Kalshi had demonstrated a reasonable chance of succeeding on its argument that the contracts were swaps covered by federal derivatives law.

New York has produced another unfavorable ruling for the company. A federal judge in July rejected Kalshi’s injunction bid, leaving the state’s gambling-law claims against its sports event contracts in place while the litigation proceeds.

State and local challenges have continued during August. Baltimore sued Kalshi and Polymarket on Aug. 13 over alleged unlicensed sports betting, with the Kalshi complaint naming Coinbase, Robinhood and Webull because the platforms distribute its event contracts to their customers.

Baltimore alleged that contracts covering game winners, point spreads and player performances operate like sports wagers without the licenses and consumer protections required under state law. Kalshi rejected that characterization and maintained that its federal regulatory status permits it to offer the contracts.

The city is seeking statutory penalties, customer restitution and disgorgement of proceeds it alleges came from unlawful activity, along with an order preventing the companies from offering unauthorized sports betting to Baltimore residents.