The relationship between Anheuser-Busch Cos. and Grupo Modelo hasn't been one of close drinking buddies.

Since Anheuser-Busch bought a stake in Grupo Modelo 15 years ago, the partnership has been tense at times. And in the moment when the St. Louis brewer might look to buy out its partner as a way to shrug off InBev's bid, analysts have said Grupo Modelo may offer up a cold shoulder instead of a cold brew.

The Mexico City-based company — maker of Corona, Modelo Especial and 10 other brands — is the top brewer in Mexico but ranked as the 10th-largest international brewer in 2007 based on volume, according to trade publication Beer Marketer's Insights.

Grupo Modelo's connection to St. Louis started in 1993, when Anheuser-Busch bought a 17.7 percent interest in the company for $477 million. The deal with Anheuser-Busch was beneficial because Grupo Modelo "didn't have a lot of access to capital at the time," said Tufic Salem, a beverage analyst for Credit-Suisse in Mexico City.

Anheuser-Busch later increased its stake to direct and indirect ownership totaling 50 percent of Grupo Modelo. But the U.S. brewer has never had the rights to distribute the Mexican company's brands in the United States.

Grupo Modelo formed a Chicago-based joint venture, called Crown Imports LLC, with Fairport, N.Y.-based producer, importer and marketer Constellation Brands to import and distribute the Grupo Modelo brands — instead of using Anheuser-Busch's connections.

The separation is, in part, why the relationship between the two brewers has been "pretty frosty," said Benj Steinman, publisher and editor of trade publication Beer Marketer's Insights.

Some say the distance hasn't changed.

"I don't think they (Grupo Modelo) believe they need A-B anymore," Salem said.

But cutting ties might be difficult. Grupo Modelo doesn't have the option to buy back the shares, unless Anheuser-Busch wanted to sell them, and that's unlikely, Salem said.

He said five families control Grupo Modelo, but little is known about the relationships among the groups. The most influential member, Salem said, is Antonino Fernández, uncle of Grupo Modelo CEO Carlos Fernández and the Fernández family patriarch.

Together, the families are "very conservative" in managing the business, rarely taking investment risks, said Marco Reyes, an analyst for Ixe Casa de Bolsa in Mexico.

"They have no debt. They never leverage their growth" by borrowing money to expand their business, said Eduardo Garcia, editor in chief of financial news website Sentido Común, based in Mexico City. "They do it the old-fashioned way. … They've grown with their own resources."

It's unlikely, then, that the families would take on the necessary debt to buy back Anheuser-Busch's stake in Grupo Modelo, according to a June 16 research note by Credit-Suisse analyst Carlos Laboy. But Laboy and other analysts have noted that Antonino Fernández and the other families have resisted giving up control of Grupo Modelo.

Whether Anheuser-Busch might be able to strike a deal is the big question, Garcia said.

"Everybody has a price, but they're very proud of what they've built," he said. "And they're very proud of being a Mexican company."