(Bloomberg) -- Fox Corp. said it filed an arbitration claim over the value of its stake in FanDuel, a fast-growing sports-betting business majority owned by Irish bookmaker Flutter Entertainment Plc.

The dispute ties back to a deal the two companies made when Flutter was acquiring the Stars Group in 2019. Fox, which already had a business venture with Stars, agreed to acquire an option on an 18.5% interest in FanDuel, a business Flutter controlled.

Fox Chief Executive Officer Lachlan Murdoch said at an investment conference last month that the two companies have differing opinions on the exercise price of that option. Murdoch said the valuation should be based on what Flutter paid the minority shareholders of FanDuel for their stake last year.

“That’s our reading of it,” Murdoch said. “There is a spread between what Flutter paid and market.”

The market value of sports-betting operators has soared in the past year as more states have legalized such wagers and consumers have embraced the pastime. DraftKings Inc., an industry leader, has more than tripled in market value since its merger with a blank-check company in late April 2020 and is now worth $25 billion.

Flutter, then called Paddy Power Betfair, merged its U.S. business with FanDuel in 2018 in a deal that valued FanDuel at less than $1 billion. That deal is also the subject of litigation from FanDuel’s founders and earliest employees. In December, Flutter paid $4.18 billion for the 37.2% stake in FanDuel owned by a group of institutional investors.

CNBC reported earlier on the arbitration claim.

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