A potential stock market listing of Flutter Entertainment’s fast-growing FanDuel business in the United States will be delayed, after FanDuel’s chief executive said he was leaving  the role.

Shares in Flutter, which also owns gambling businesses including Paddy Power and Betfair, were 3.5pc lower by lunchtime yesterday as investors reacted to the latest challenge for the group.

Matt King, who has headed FanDuel for the past four years, will remain with the group until a successor is found.

Flutter said Mr King had overseen the transformation of FanDuel from an online daily fantasy sports operator to the marketing leader in US online sports betting and gaming.

“As previously announced, the Flutter board has been assessing the merits of listing a small stake in FanDuel in the US,” added the company.

“Whilst Matt’s departure will affect the timing of any potential US listing, the board will continue to keep this option under review,” it said.

Flutter upped its stake in FanDuel last December to 95pc in a deal that implied an enterprise value of $11.2bn for the US business. But Flutter bought the additional stake at a significant discount to FanDuel’s fair value, paying $4.18bn for a 37.2pc holding.

Last May, Flutter completed its €12bn merger with the Stars Group. That saw Fox Corporation, which had a stake in Stars, secure a 2.6pc holding in Flutter.

As part of the deal announced in December, Flutter offered Fox Sports an option to buy 18.5pc of FanDuel at fair market value in July this year.

But Flutter and Fox are now at loggerheads over that option.

Fox has initiated an arbitration process in the United States, claiming it should be permitted to exercise that option based on the price Flutter  paid for its stake in December. 

Flutter maintains that the option should be exercisable at the fair value of the stake next July.

The arbitration process is underway in New York.

Reporting first quarter results last month, Flutter said that its revenue approached $400m in the United States in the period, up 135pc year-on-year and mostly generated by FanDuel.

Flutter had an average of 1.6 million online customers in the quarter in the US, making it twice the size of Flutter’s Australian arm.