(Reuters) -Flutter Entertainment said on Wednesday Matt King, the chief executive officer of its FanDuel business, will be leaving the company and the betting group warned his exit would delay FanDuel's potential U.S. listing.
Flutter's London-listed shares fell more than 2% after the news.
The owner of Paddy Power, Betfair and PokerStars also said it was keeping the FanDuel floatation under review and was looking for a successor to King.
"With FanDuel well positioned for the next chapter of its growth and always an entrepreneur at heart, now is the time for me to take on new opportunities as the next step in my career," King said in a statement.
Flutter said King had been the top boss at FanDuel for four years and that he had overseen the growth of the online sports betting and gaming business after a 2018 lift on a ban on sports betting made the United States the next big growth market.
Last month, Flutter reported that its first-quarter U.S. sales more than doubled almost exclusively through FanDuel, in which the Irish company increased its stake to 95% through a $4.2 billion deal in December.
King's decision to leave FanDuel was "clearly a disappointment," analysts at Davy Research said in a note.
However, they added that the role is likely to attract "high calibre" candidates because of the opportunity to lead the "best positioned" U.S. sports betting operator.