Boots Group PLC, the UK largest drugstore chain, may be offered a buy-out deal by at least four private-equity firms, including Blackstone Group and Texas Pacific Group, people familiar with the matter said.

The deal, probably worth as much as £4.6 billion ($8.7 billion), has four main companies to launch: Blackstone Group, Texas Pacific Group of the U.S. and CVC Capital Partners Ltd., Cinven Group Ltd. of the UK.

The companies are said to have had consultations with potential advisors, but final decision was not made by any of them.

"It is clear that we are now, and will be for the foreseeable future, operating in a much more difficult trading environment in which sales growth will be hard fought for and cost pressures will continue to rise," said Boots Chief Executive Richard Baker.

The company reported Thursday its performance for the fourth quarter was far from stellar. It has posted a 0.9% drop in sales comparing with the year earlier records.