UPDATE 2-UK pension transfer boom continues as deals worth $11 bln struck

(Adds Co Op deal, regulatory comments)

By Lawrence White

LONDON, Nov 24 (Reuters) - Two British insurers on Friday struck deals to take on a combined 8.8 billion pounds ($11 billion) of company pension liabilities, including the largest such UK deal so far, as pension schemes strive to limit their risks in volatile markets.

Legal & General said it had agreed a so-called full buy-in to the Boots Pension Scheme worth 4.8 billion pounds, in what it said was the largest such deal in Britain by premium size.

Pension insurance specialist Rothesay, meanwhile, said it had concluded a 4 billion pound buy-in with a section of the pension scheme sponsored by Co-operative group, whose businesses include food, funerals, insurance and legal services.

Also known as bulk annuity deals - where trustees of pension schemes pay a premium for the insurers to assume some of the liabilities - the agreements form part of what is set to be a record year for such transactions.

The market has been running at around 30 billion pounds a year in Britain, but consultants expect 2023 to top that.

Regulators have expressed concerns about the trend, with the Bank of England's Prudential Regulation Authority warning last week that life insurance companies involved in such business should limit exposure to reinsurers due to risk that those businesses - sometimes based overseas - run into trouble.

Insurers often sell on some liabilities to reinsurers.

Rising funding ratios for pension schemes are driving unprecedented demand, Legal & General (L&G) said, as funds scramble to protect schemes against the vagaries of market movements amid rising interest rates worldwide.

L&G has written a total of 13.4 billion pounds worth of pension risk transfer deals this year globally, up from 9.5 billion pounds last year. Its solvency ratio of an estimated 224% puts it in a strong position to pursue more such business, the company said.

Health and beauty products provider Boots, with over 2,000 stores and 52,000 staff, is one of Britain's oldest and best known high street brands.

($1 = 0.8025 pounds) (Reporting by Eva Mathews in Bengaluru and Lawrence White in London; Editing by Sharon Singleton and Mark Potter )