Allied Domecq was one of the biggest risers on the FTSE 100 on Monday after a US firm said it was interested in joining a bid battle for the firm.
Constellation may want Allied's champagnes more than Malibu
The UK drinks company, maker of Malibu, last week accepted a £7.4bn ($14bn) takeover bid from Pernod Ricard of France and Fortune Brands of the US.
But the world's largest winemaker, Constellation Brands, said it was considering a rival bid for Allied.
The US firm would need partners for a bid as it is not big enough by itself.
Allied would have to pay a penalty of £37m if it accepted a rival takeover bid within half a year, reports say.
But Constellation said it was not yet ready to make a formal takeover offer.
"Constellation is at an early stage of evaluating its options with a number of potential partners and there is no certainty that this process will lead to an approach being made to the company," it said after being forced to issue a statement by the UK's Takeover Panel.
CONSTELLATION DRINKS BRANDS
Wine - Banrock Station, Hardy's, Stowells, Turner Road, Echo Falls, White Cloud, Shamwari, Paul Masson
Cider - Addlestones, Blackthorn, Diamond White, K, Olde English, Red C, Natch, Special VAT
Fortified wines - VP, QC, Tudor Road, Stone's Ginger Wine
Wine-style - Babycham, Rougement, Arbor Mist, Country Manor
Strathmore mineral water
Possible partners for Constellation, known for its Hardys wine and Corona beer, could include Bacardi, the rum company, and Brown-Forman, which makes Southern Comfort and Jack Daniels American whiskey.
Other companies, which might consider partnering with Constellation, according to press reports, include luxury goods company LVMH and drinks businesses Diageo and Suntory.
Constellation is thought to be interested in Allied's wines business, which includes Mumm and Perrier-Jouet champagne.
Other Allied brands include Beefeater Gin and Courvoisier cognac.
Shares in Allied, the world's second largest drinks company, closed up 8.5p, or 1.3%, at 671.5p on Monday.