UPDATE 1-Paddy Power Betfair says CEO Corcoran to step down

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DUBLIN, Aug 7 (Reuters) - Gambling firm Paddy Power Betfair's chief executive Breon Corcoran announced plans to step down on Monday, 18 months since completing the merger of Irish bookmaker Paddy Power with British online betting exchange operator Betfair.

The company's share price was down 7.4 percent at 73.39 pounds in London trading by 0750 GMT, extending losses since the start of the year to 16 percent.

Corcoran will be replaced by Peter Jackson a non-executive director at Paddy Power Betfair and CEO of the UK arm of global payments business WorldPay Group since March, the company said in a statement.

Worldpay Group is currently negotiating its own sale to U.S. peer Vantiv.

Shares in Paddy Power Betfair were down 7.4 percent at 73.39 pounds in London trading by 0750 GMT, extending losses since the start of the year to 16 percent.

The company gave no date for Corcoran's departure, saying only that he would "complete the integration of the Paddy Power and Betfair businesses and ensure the delivery of an orderly transition."

Paddy Power also reported details of its financial results for the first six months of the year a day early, reporting revenue growth of 9 percent and underlying EBITDA growth of 21 percent and said trading was in line with expectations.

It said it expected underlying earnings before interest, tax, depreciation and amortisation expenses (EBITDA) this year of between 445 million pounds and 465 million pounds ($580-607 million).

The average forecast of six analysts polled by Reuters in recent weeks was 459 million euros.

"The timing is certainly less than ideal given the particularly noisy regulatory backdrop at present and the fact that the group is yet to complete its major platform migration project," said Davy Stockbrokers analyst David Jennings.

"That said, the fact that the board is in a position to announce Peter Jackson as CEO designate should provide some comfort."

Corcoran has been CEO of the group since the completion of the merger in February 2016, having served as CEO of Betfair Group since 2012. Before that he was chief operating officer at Paddy Power, where he had worked since 2001.

Jackson was CEO of Travelex Group from 2010 until its sale in 2015 and was in charge of innovation at Banco Santander before his appointment as CEO of WorldPay's UK arm.

Paddy Power Betfair Chairman Gary McGann said the company "intensified (its) focus on executive succession planning" a few months ago after Corcoran spoke to the board about his long term plans. ($1 = 0.7661 pounds) (Reporting by Rahul B in Bengaluru and Conor Humphries in Dublin; Editing by Greg Mahlich)