Saquon Barkley has built a reputation as one of the NFL's busiest investors off the field. One of those bets had to go. The Philadelphia Eagles running back says he was forced to sell his stake in the prediction market company Polymarket because of league rules.

"I was in it before, but no bueno," Barkley said.

NFL rules bar players from holding investments in gambling companies. The players' union says the league views prediction markets the same way it views sportsbooks.

A big startup portfolio

Barkley has put more than $500,000 into startups. His portfolio has included the AI company Anthropic, the defense tech firm Anduril, the finance company Ramp, the AI coding startup Cognition, Neuralink and the bitcoin payments company Strike. Polymarket was on that list until he was told to sell.

Leagues split on prediction markets

The NFL is taking a harder line than other leagues. The NBA, MLB, NHL and MLS all have partnerships with Kalshi, Polymarket or both.

The NFL has pushed back. Earlier this month the league asked the Supreme Court to review whether contracts tied to sporting events should be allowed.

What it means for players

For now the rule is clear. Players can invest in plenty of fast-growing companies but prediction markets are off limits. Barkley's case shows how quickly that line can catch up with a player who invested early.