Yesterday, Anheuser-Busch InBev approached rival SABMiller with a takeover offer that, if successful, would combine the world’s two biggest brewers into one global beer behemoth.

"AB InBev's intention is to work with SABMiller's Board toward a recommended transaction," the Belgium-based brewing company said in a statement posted on the company's website. "There can be no certainty that this approach will result in an offer or agreement, or as to the terms of any such agreement."

With sales in over 100 countries, AB InBev is the world's largest brewer and has a 25% global market share. It produces more than 200 beers, including Budweiser, Corona, and Stella Artois. SABMiller boasts aggressive figures of their own; in the year ended March 31, the company sold 324 million hectoliters of soft drinks, lager, and other alcoholic beverages, producing net revenue of $26.2 billion.

Despite each company’s imposing revenue statistics, all is not well in the world of Big Beer. According to Beer Marketer’s Insights, the U.S. market share Anheuser-Busch and MillerCoors was 47.7% and 29%, respectively, just five years ago. In 2014, those market share figures dropped to 44.7% and 26%. Meanwhile, craft beer accounted for 11% of U.S. beer sales that same year – the first time that segment reached double digits.

But the two global beer giants are taking necessary precautions. Last week, MillerCoors took a majority stake in Saint Archer, a San Diego craft brewery known for its ales. Just days earlier, Heineken said it would take a 50% stake in Lagunitas Brewing Co., a popular California-based craft brewer known for its irreverent business model.

Though their shares have decreased, AB InBev and SABMiller shipped more than 70% of the beer produced for the U.S. market in 2015. A merger would surely provoke antitrust scrutiny in the United States. To resolve these concerns, beer industry observers have said the U.S. Department of Justice will likely force SABMiller to sell its share of MillerCoors. Molson Coors, the co-owner, would be a likely buyer.

But we can’t know any of this until Anheuser-Busch makes a formal offer. The company has until 5 PM on Oct. 14 to make an offer or walk away under U.K. industry rules.