If you're grabbing a beer after work today, chances are it's made by one of four companies.

According to a report on Tuesday from Bank of America Merrill Lynch, Anheuser-Busch InBev, SABMiller, Heineken, and Carlsberg together produce about half of the world's beer.

This enormous market stake comes after 15 years of what the analysts call "massive industry consolidation."

The consolidation has been quite fast. In 2004 the industry's top 10 brewers controlled 51% of the market volume. By 2014, 47% of the market was held by just 4 companies. In other words, the top 4 companies today control nearly as much market volume as the top 10 companies did just a decade ago.

Furthermore, BAML says that these 4 companies control about 74%, of the industry's $33 billion global profits, as illustrated by the chart below.

These 4 companies have a staggering amount of global, regional and local brands, as well as a large number of joint ventures and minority stakes in other brewing companies.

Interestingly, each company is also a major player in the soft drink industry, with each owning Coca Cola and/or Pepsi franchises in various countries across Europe, Africa, and Latin America.