Billionaire Thomas Tull is vying against rival bidders as he seeks to increase his ownership in the NFL’s Pittsburgh Steelers by acquiring a small stake from sports investors Josh Harris and David Blitzer, according to people with knowledge of the matter.

Harris and Blitzer bought a stake of less than 5% in the team in 2020, Bloomberg News has reported. They’re exploring a sale after a group led by Harris won the auction for another team in the league, the Washington Commanders, earlier this year. NFL rules mandate that a majority owner can’t hold an interest in another franchise.

Read more: Josh Harris Seals High Finance’s Status in NFL’s Inner Circle

Tull, who is based in Pittsburgh and a longtime Steelers fan, has been a co-owner in the team since 2009. It isn’t clear how the franchise’s valuation would be impacted by such a transaction, and it’s possible other interested parties will prevail, cautioned some of the people, all of whom requested anonymity discussing confidential talks.

Representatives for Tull, Harris and Blitzer declined to comment.

Tull, who has a net worth of about $3 billion according to the Bloomberg Billionaires Index, cemented his fortune by selling Legendary Pictures, the production company behind films like The Hangover and The Dark Knight. He now focuses on backing artificial intelligence startups, among other ventures.

The Steelers are majority-owned by the Rooney family, which counts actresses Rooney Mara and Kate Mara among its heirs. The team has won six Super Bowls, with its most recent win coming in 2009.

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(Updates with Steelers context in last paragraph)