Belgian brewer InBev warned U.S. rival Anheuser-Busch on Sunday that it should fully explore its $46 billion takeover offer before striking out to do any potential deal with Mexico's Modelo.
In a letter that appeared aimed at Anheuser-Busch shareholders, InBev suggested that doing a deal with Modelo could impact the value of its $65-a-share takeover offer.
InBev, whose beers include Stella Artois and Beck's, on Wednesday made an unsolicited bid to buy Anheuser-Busch, which brews the popular Budweiser brand. A deal would create the world's largest brewer.
St Louis, Missouri-based Anheuser-Busch responded that its board would evaluate the proposal carefully.
On Friday, The Wall Street Journal, citing people familiar with the matter, reported that Anheuser-Busch had begun talks with Mexico's No. 1 brewer, Grupo Modelo, about a possible combination of the two companies that could help it thwart the Inbev bid.
Anheuser-Busch owns a 50 percent stake in Modelo, maker of Corona beer, which is emerging as a critical power broker in the battle for control of Anheuser-Busch.
In the letter, dated Sunday, Inbev's Chief Executive Carlos Brito told Anheuser-Busch's CEO August Busch IV that he was committed to a "friendly combination." But he said: "We have read the recent press reports suggesting that you may have approached Grupo Modelo regarding a possible transaction between Anheuser-Busch and Grupo Modelo or affiliated entities."
He said it was important that Anheuser-Busch understood that Inbev's offer was "made on the basis of Anheuser-Busch's current assets, business and capital structure."
"Accordingly, we would expect that prior to proceeding with any alternative transaction, especially if your shareholders will not be given the opportunity to vote on it, you would first fully explore our offer and the potential adverse consequences any such transaction could have on the ability of your shareholders to receive our premium offer," he said.
Brito added that InBev believed that no alternative transaction Anheuser-Busch could clinch would create more value for its shareholders than the $65-per-share in cash it is offering.
"We are convinced that your shareholders would reach the same conclusion," he wrote.
The letter did not say, however, that Inbev would pull out if Anheuser-Busch struck a deal with Modelo.
The letter also made no mention of any discussions InBev may itself have had with Modelo.
CNBC television reported on Friday that InBev would "be happy" to let Modelo buy back its stake, and a source familiar with the situation told Reuters that InBev is believed to have already reached out to Modelo.
Modelo has multiple options according to analysts.
It could try and buy back its stake from Anheuser-Busch, or from InBev if a deal is struck.
It could keep the status quo in search of a better negotiating table with InBev down the road, or it could sell out to Anheuser-Busch.
Shares of Anheuser-Busch closed on Friday at $61.12, down 28 cents on the day.
Shareholders in Anheuser-Busch include Warren Buffett's Berkshire Hathaway <BRKa.N>, which has a 5 percent stake.
Anheuser-Busch declined comment.
Modelo was not immediately available for comment.