This is more than an unfounded rumor
There are constant talks of acquisition in the beer industry, and ABI has speculated about a purchase of this size before. Sometimes they happen; often, they don't.
But this time is different. "This seems real," Gatza said. "Within the industry, people are treating it like it's happening."
The additional certitude, he said, stems from a financial law in the UK that requires corporations to disclose prospective mergers after a certain point. Once ABI approached SABMiller (which is publicly traded on the London stock exchange), the latter company was obligated to tell regulators. Even if the sale doesn't wind up happening, the companies have definitely talked.
The two companies control almost 75% of the US beer market...
Anheuser-Busch/InBev comprises a staggering array of brands, but its biggest are Bud Light and Budweiser, the first- and third-best-selling beers in the country respectively, according to a 2014 study from IRI, a Chicago market-research firm. The dominance of the company's flagship brews contributes to a whopping 45% share of the US market.
The same study shows Coors Light & Miller Lite sitting in second and fourth places. Both are part of MillerCoors (28% share of the US market), a partnership that's joint-owned by Molson Coors and SABMiller (which holds the majority stake). A sale like this could put as much as 73% of America's beer in one mega-company's hands. Of course, this would have to be approved by US anti-trust regulators, which would appear unlikely. But still: this is a LOT of the US beer market we're talking about.
...30% of the global beer market...
Beyond Uncle Sam's jurisdiction, though, the situation is different. The two companies control less of the world's beer than they do of the United States' beer -- around 30%, according to the Wall Street Journal -- but the international business is less stringently regulated. "The idea of monopolies is of strong interest in the US, but it’s of relatively small interest pretty much every else," said Gatza.
That doesn't necessarily spell disaster for international drinkers, he noted, pointing out that in many countries, ABI and SABMiller don't compete with each other as heavily as they do in the US. "One or the other is usually bigger" in a given region, where they face heavier competition from other top companies like Carlsberg, Heineken, and Constellation. An exception: China, the other major market where regulators may force ABI to divest in the event of a merger.
...And $70 billion in global revenue (over 3x the next biggest beer company)
Last year, SABMiller posted a revenue of $22.3 billion. ABI claimed $47.06 billion. The four flagship beers alone (Bud Light, Coors Light, Budweiser, Miller Light) represent $10 billion in annual revenues, according to IRI. For comparison, the entire craft beer industry is worth around $20 billion, split amongst around 4,000 brewers. For more comparison, Heineken International, which would become the second-biggest beer company if the merger went through without regulation, is also worth about $20 billion (pdf) -- less than a third of the new entity.
In other words, this new company would be a financial beer behemoth -- "the last piece," as Gatza called it, to a flurry of acquisitions that's been going on since the '90s.
Expect the federal government to do some anti-trusting US regulators have traditionally been pretty attentive to the country's beer industry, and probably will be in this case, as Gatza hypothesized in a blog post. When ABI acquired Modelo, the DOJ required "a sell-off to Constellation Brands-Beer Divsion, so it is hard to think that they would allow absorption of Miller [brands]"
Wait, what? Aren't they buying Miller and its brands?
Well, yes. But they may not be permitted to keep those brands in the US. Like all global industries, Big Beer can get pretty confusing, but the basic idea is that in the event of an acquisition, ABI would probably be required by the federal government to divest itself of control of SABMiller's US component (MillerCoors) by selling it. To whom? "Molson Coors or other large international entities," guessed Gatza, including "Constellation Brands—Beer Division, Heineken or Carlsberg" or even non-beer conglomerates.