Without naming a source, The Sunday Times reported that SABMiller (OTC: SBMRY.PK), the world's second-largest brewer, was preparing to purchase the highly profitable beer unit of Foster's Group, ahead of Foster's plans to demerge its beer and wine groups sometime early next year.

If true, this would be the latest shot in the global war for beer market dominance among such giants as Anheuser-Busch InBev (NYSE: BUD), Diageo (NYSE: DEO), and Molson Coors (NYSE: TAP), among a handful of others.

Whether it's true, the rumor highlights the fact that big brewers are thirsty for more market share right now. The year 2008 saw a flurry of consolidation activity in the developed markets, with companies making acquisitions, mergers, and joint ventures in order to find growth in synergies rather than sales.

Growth in these developed markets averaged an annual decline of 3.4% over the past five years. The real growth has been in the emerging markets, which averaged 6.8% in the same period, pushing the global beer market to 3.5% growth. A growing middle class in countries such as Brazil, China, India, and parts of Africa wants to start living the (Miller) High Life that some of us take for granted.

But this raises the question: Why are big brewers tipsy for Foster's, and not something located in an emerging market, like China's Tsingtao, or Phoenix Beverages in Mauritius? The answer is twofold.

First, the Foster's brand has already been carved up globally. Heineken (OTC: HINKY.pk) owns the rights to the brand in Europe, and SABMiller owns the brand in India and the United States. Buying the entire beer division from Foster's Group, then, would allow Heineken or SABMiller to round out the rest of the available brand. In 2006, when SABMiller acquired Foster's India, the Indian branch had been growing 13% annually since operations began in 1998. SABMiller, originally a South African company, is known for focusing on emerging markets, and could use that expertise to re-create the Indian growth in other new markets.

The second reason for Foster's appeal is the fact that it controls roughly 50% market share in Australia, a position which lends itself to heady 38.5% profit margins, eclipsing InBev's 27.9% or Heineken's 12.4%. Australia itself is the eighth most profitable beer market in the world, so controlling that kind of market with that kind of a profit margin is enough to make anyone lightheaded.

What this comes down to is that, while growth in developed markets may be down in aggregate, that's really only a statistic about the customers. Brewers in these markets shouldn't be ignored, as they are still able to turn a profit through market dominance or expansion into more untapped markets -- or, in the case of a Foster's acquisition, both.

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Fool contributor Jacob Roche holds no position in any of the companies mentioned. He also serves Motley Fool Options as a Community Fool. SABMiller is a Global Gains recommendation. Diageo is an Income Investor recommendation. The Fool owns shares of Diageo. The Motley Fool has a disclosure policy.