LeBron James makes Polymarket partnership public before Tuesday reveal

LeBron James made his Polymarket partnership public in a video posted to X. Polymarket promised a full reveal on Tuesday. The terms of the partnership remain undisclosed. The video shows James inside an elevator at what he calls Polymarket headquarters. He passes buttons for politics, crypto, the economy, culture, weather, esports and technology. He exits on the sports floor. James endorsed sportsbook DraftKings from 2024 until that deal expired earlier this summer. He appeared at Polymarket weeks later. Prediction market sector volume topped $20 billion a month by January. That volume was up from roughly $1.2 billion in early 2025. Betting on James's next team drew more than $245 million in volume this summer. The NBA allows players to endorse prediction markets. The NBA bars players from promoting contracts tied to NBA games. The NFL and PGA Tour reportedly ban such deals outright. Giannis Antetokounmpo became a Kalshi shareholder earlier this year. That move intensified competition between Kalshi and Polymarket. Polymarket became Major League Baseball's official prediction market provider. The NHL made deals with both operators in October 2025. Baltimore sued both operators in August. Baltimore called them unlicensed sportsbooks. New York sued Kalshi in July for more than $36 billion. Polymarket sought $400 million at a $15 billion valuation in April. That valuation exceeded the $9 billion valuation it had in October. Intercontinental Exchange committed $2 billion to Polymarket. Polymarket added Pokemon card markets in August. The campaign arrives as football season starts. The coming weeks should show whether star power converts curious fans into active traders.