LeBron James Signs Reported $8M Deal With Polymarket, Fueling Prediction-Market Boom
LeBron James joins Polymarket in a reported $8-million, two-year deal, deepening the celebrity arms race between rival prediction markets Polymarket and Kalshi.
This article was produced with AI assistance and edited by the ON360 newsroom.
NBA legend LeBron James has signed a reported two-year, $8-million deal to promote Polymarket, according to Gambling Insider, the latest and most prominent athlete tie-up for a prediction-market platform still fighting for legal footing in several U.S. states.
The partnership, announced earlier this month, has James making weekly NFL picks on the platform. A companion ad campaign also features Sue Bird, Reggie Bush, Derek Jeter, Eli Manning, Rajon Rondo and Richard Sherman, alongside appearances from filmmaker Spike Lee.
From betting critic to prediction-market pitchman
James previously fronted ads for DraftKings Sportsbook. Three years ago, though, he criticized how online sports betting was affecting the game he plays.
“It’s kind of taken some of the integrity out of the game because people are kind of really only caring about the betting,” James said at the time, according to Gambling Insider.
The reversal did not go unnoticed. Social media analyst Brett Dashevsky ran sentiment analysis on the paid partnership posts from James, Jeter and Manning, and found similarly negative reactions across all three, Gambling Insider reported.
Kalshi still holds the bigger star roster
Polymarket’s deal comes as it plays catch-up to rival Kalshi, which leads on valuation, trading volume and celebrity backing. Milwaukee Bucks star Giannis Antetokounmpo’s arrangement with Kalshi reportedly includes an ownership stake, while golfer Bryson DeChambeau and soccer star Lionel Messi both served as Kalshi brand ambassadors this summer.
Kalshi has also struck agreements with five Major League Baseball clubs: the Atlanta Braves, Boston Red Sox, Los Angeles Dodgers, San Diego Padres and San Francisco Giants. Polymarket, meanwhile, was named MLB’s exclusive Official Prediction Market Exchange back in March.
The legal fight that could undo it all
Both platforms are still contesting whether sports event contracts can operate outside state gambling regulation, with multiple state regulators pushing back and the dispute widely expected to reach the U.S. Supreme Court. A ruling against sports contracts would strip prediction markets of the product driving most of these athlete deals.
None of that changes the near-term picture for Polymarket and Kalshi. Each additional athlete, team or league partnership makes the platforms look more established, which analysts say strengthens their argument in court that they belong in the mainstream rather than under state betting rules.
Neither Polymarket nor Kalshi is licensed or registered in Ontario. Bettors here have access only to sportsbooks and casino operators registered with the AGCO and offered through iGaming Ontario, all of which must provide deposit limits, self-exclusion and other responsible-gambling tools.
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