How much spare capacity does AB have in the US?

You probably need an insider to actually answer this question. It would require a tremendous knowledge of manufacturing operations at the company.

One thing I can say for sure is top notch companies don't let capital investments (read: equipment) sit idle. They will find a way to use it, introducing new brands, promoting others, leasing equipment to other companies, etc.

The bottom line is letting millions of dollars in manufacturing equipment sit unused is a total recipe for disaster. The automotive manufacturers, Chrysler, GM, had to let plants sit almost idle in 2009-2010, because no one was buying cars. I can only imaging this was a major contributor to the reason they required a bail-out. They still had to pay their creditor dues on their debt, for the facilities they built in the past 5-10 years, but weren't generating any revenue.

Bottom line is smart companies use their investments wisely. And although we may not like AB Inbev's beer, stockholders sure like the company over the past 5 years.

 

A few years ago, and a previous website design IIRC, AB listed their US breweries' capacities which added up to around 110 million barrels. The last few years their total US sales (so, both domestic and ABInBev imported brands) have been in the 95-97 million bbl range (down from a peak ~107m bbl in 2008). So, the answer is "Enough", especially considering the relatively small US sales of RR, GI, Bass and Beck's (all less than 1% of their total barrelage) compared to the multimillion barrel flagships like Bud Light and Bud.

This is a popular misconception. Rolling Rock's Latrobe Brewing Co. was at the time owned by Labatt, an InBev company. InBev wanted to unload it - their preference would have been some company that would buy both the brand and the physical brewery. When such a buyer could not be found, they sold the brand to Anheuser-Busch and, a few months later, the Latrobe brewery to City Brewing Co. AB did not sell the brewery - since they never owned it.

That chronology is today complicated by the fact that the two companies, seller and buyer, are now one - ABInBev. There was even some speculation at the time that the sale of Rolling Rock to AB in 2006 and a few months later the deal that transferred most of the import rights of the InBev brands to AB's Import Brands Alliance gave InBev knowledge of AB internal financial situation and made their bid for the brewery easier a few years later.

Others joked that InBev realized what a mistake they made selling Rolling Rock and had to buy all of Anhueser Busch just to get it back .