Allied Domecq shares rose more than 3 per cent today.
The share rise came after the spirits company said it received a bid approach from a US group that could derail an agreed $14 billion bid led by France's Pernod Ricard.
Allied shares rose to 695p a share in early trading, above the agreed deal value of about 670p a share; Pernod slid 2.5 per cent to €117.9.
"Although the preliminary approach is not a firm bid, the emergence of a potential rival offer for Allied creates some further uncertainty for Pernod," Lehman Brothers said in a note to clients, pointing to regulatory issues Pernod also needs to overcome to win the maker of Ballantine's whisky and Beefeater gin.
Allied said yesterday it had received a bid approach from a group led by Constellation Brands, the world's largest wine company, and including US drinks group Brown Forman and buy-out firms Lion Capital and Blackstone.
A source said Constellation had not named a price but had made clear its offer would be above Pernod's.
Allied agreed last week to be acquired by Pernod Ricard and US partner Fortune Brands for 545p a share in cash and 0.0158 Pernod shares for each Allied share.
Under UK Takeover Panel rules, however, Allied will now have to open its books to the Constellation consortium and a spokesman for the US group said the aim was to get a firm offer on the table as soon as possible.