If Modela is based in Mexico it cannot be 50% owned by BUD. Mexican law prohibits their companies to be more than 49% foreign owned, a fine point usually missed by journalists who "report" on such things.
IOW, Modela is a Mexican company with a large US investor.
From the A-B website:
Mexico is also an excellent market for Anheuser-Busch. It is the world's second largest beer market in operating profits, behind only the United States, and has experienced strong volume growth over the past five years, growing an average of 2 ½ percent per year, Baker said. Anheuser-Busch has a 50 percent stake in Modelo, which has a 56 percent share of the Mexican beer market and its Corona brand is the No. 1 import in the United States.
“Our international beer segment is making a significant contribution to
Anheuser-Busch's earnings growth, and we are strategically well positioned for long-term growth with our expanded position in China and our 50 percent ownership of Modelo,” observed Baker.
But can Modelo keep sales of Corona from going flat? At first glance, you would hardly think this was an issue for 38-year-old CEO Carlos Fernández. The family-run brewer, in which Anheuser-Busch Cos. (BUD ) holds a 50.2% stake, commands a leading 56% share of the Mexican beer market through a portfolio of brands that also includes Modelo Especial, Negra Modelo, Victoria, and Pacífico.
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http://www.businessweek.com/magazine/content/05_06/b3919098_mz058.htm
FWIW, although BUD owns 50%, control of the company lies with the Modelo owners (I don't know how ... I think it stems from an legal decision in the early 90's).