New York-based KKR is said to have withdrawn over regulatory issues connected to its Alliance Boots bidding.
However its exit is thought to be just one of the conglomerate's issues, which includes heavyweights CVC, Blackstone and Texas Pacific.
Rumours of unhappiness in the Sainsbury family camp over the proposed bidding prices have continued to circulate in the press.
According to the Times, an offer has been pitched to the board at between 550p and 555p a share.
Yet the Daily Telegraph cited an unnamed source, thought to be close to Lord Sainsbury, as saying: "He cannot see any reason why the board would even consider opening the books at less than 600p-share."
None of the parties involved have provided a response to such rumours.
The consortium has until April 13th to make an offer, a deadline set by the UK's takeover watchdog.
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