KKR is to invite rival private equity groups to participate in its joint £10 billion bid for Alliance Boots as minority investors if the deal receives a recommendation from the group’s board.

Stefano Pessina, the deputy chairman of Alliance Boots, and KKR raised their offer from £10 to £10.40 a share yesterday, prompting the company to open its books for a limited period, believed to be about three weeks, to allow due diligence work.

The deal, if completed, would also lead to Mr Pessina investing up to £1 billion of his own money in what would be Europe’s biggest leveraged buyout. Debt financing is in place through their banks, Merrill Lynch, JPMorgan Cazenove and Unicredit, the Italian bank. Other banks are also likely to join the group if a firm offer is made.

Yesterday Mr Pessina and KKR emphasised that their plans for the company, which employs more than 100,000 people and operates about 3,000 pharmacies across Europe and Thailand as well as a drug wholesaling business serving 125,000 retail outlets, were focused on long-term growth.

KKR is believed to have approached Mr Pessina about two months ago, having worked on the idea of a buyout of Boots for several months. The two sides agreed to meet in Paris at the beginning of last month for a preliminary meeting with lawyers and after hearing KKR’s plan, Mr Pessina agreed to sign up to the buyout.

Speaking of his decision to back KKR, Mr Pessina, the architect of the £7 billion merger in 2005 to create Alliance Boots, told The Times: “With KKR we will be able to help grow this company through its development as the markets we serve are changing rapidly. We will be able to invest faster and react faster to events.”

The duo’s strategy is believed to include accelerating investment in the business, fresh acquisitions in the UK and overseas — particularly on the wholesaling side — and cost cuts. The “objective is to work with the existing management team to enhance Alliance Boots’ position as a global leader in the healthcare services and beauty industries”, they said in a statement.

Alliance Boots has agreed to set up a “data room” for KKR and any other rival bidders, and is believed to consider £10.40 a full and fair price. However, some shareholders expressed surprise that the board had opened its books at that level.

“It’s 50-50 whether they’ll get it at that price. It’s only 4 per cent more; that’s hardly going to set the world on fire,” a significant shareholder said.

A counter-offer from a rival private equity group is believed to be difficult given that Mr Pessina, who is Boots’ largest shareholder with a 15 per cent stake, has made it clear that he will not work with a competing bidder. Sources have said, however, that he could sell his stake if a rival offer is made that is much higher than his joint bid with KKR.

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