(NYTimes) - When Anheuser-Busch InBev moved to take full control of the Mexican beer maker Modelo, it thought the deal would be a cinch.

The biggest brewer in the world already controlled Modelo with a 50 percent stake, and sealing its ownership would do little to change the competitive landscape.

But United States antitrust regulators balked, fearing that the enlarged company would raise the price of popular brands like Corona. Only after a year of negotiations and promises to complete painful divestitures did Anheuser-Busch InBev win approval for the $20 billion deal last year.

Now, as the global beer business braces for another round of potential consolidation, that episode casts a long shadow over the empire-building aspirations of the remaining brewing behemoths.

On Sunday, Heineken said it had rejected a takeover offer from SABMiller, the second-largest beer company in the world. And while that deal may never happen, SABMiller’s attempt to expand through a major acquisition could produce another round of deal-making.

“There is definitely room for more megadeals,” said Marc Levit of the Demeter Group, an advisory firm that focuses on the beverages industry. “It makes a lot of sense for those looking for international growth, and inevitably will happen.”

The next round of beer deals may not be as easy as the last one. After decades of consolidation, there are myriad obstacles facing brewers that want to expand through megadeals.