UPDATE 1-Profit jumps at pension buyout specialists Phoenix

(Adds details on background, synergy target from statement)

Aug 7 (Reuters) - Insurer Phoenix reported a surge in profit in the first half of 2019 as it bought out more British corporate pension schemes, but it warned that the money coming into its open book business had been reduced by Brexit-related worries.

The FTSE-100 company, which has boomed by taking over a number of closed pension schemes from UK companies anxious to offload the long-term risks, reported a 50.5% jump in operating profit to 325 million pounds ($395.23 million) for the six months ended June 30.

While it reported an 18% drop in cash generation in the first half, Phoenix said it expects to be towards the upper end of its cash generation target of 600-700 million pounds for the year.

Phoenix, which bought the bulk of Standard Life Aberdeen's insurance business last year, said it was on track to deliver 1.2 billion pounds in savings from the deal.

The company, which has 10 million policy-holders and 226 billion pounds in assets under administration with operations in the UK, Ireland and Germany, had set a long-term cash generation target of 3.8 billion pounds for 2019–2023.

Also the owner of the SunLife life insurance brand, it said that gross inflows to its UK open business had dropped to 4.8 billion pounds in the first half from 5.5 billion pounds a year earlier, partly due to uncertainties around Brexit.

It said that its own Brexit preparations were complete with 250 million pounds of capital injected into an Irish subsidiary.

British companies are already expected to try and offload a record amount of pension schemes risk in 2019 as growth in life expectancy eases and interest rates rise, making deals more attractive for insurance firms.

A company's pension obligations sit on its balance sheet and can limit its financial and strategic options so most boards are keen to pass the burden on.

The HSBC Bank (UK) pension scheme this week sealed a deal with a subsidiary of Prudential Financial to insure around 7 billion pounds of pension liabilities, while Phoenix in May said that it had taken over 1.4 billion pounds in liabilities from Marks & Spencer's in conjunction with Pension Insurance Corporation.

($1 = 0.8223 pounds) (Reporting by Muvija M and Noor Zainab Hussain in Bengaluru; editing by Patrick Graham)