But a merger would be certain to draw antitrust reviews by regulators from many countries.

“Market power would be much increased, as the major supermarkets would have little choice but to buy from the merged business,” John Colley, a professor of practice in strategy and leadership at Warwick Business School in Coventry, England.

Kraft Heinz approached Unilever about a potential deal in the last few weeks, according to people briefed on the matter, who were not authorized to speak publicly about the negotiations.

Among its pitches, these people said, was that the combined company would maintain headquarters in the United States, Britain and the Netherlands. That could prove important amid rising nationalist sentiment, given Britain’s vote to leave the European Union and an election approaching in the Netherlands.

Kraft Heinz, with 3G behind the wheel, has long been considered the most likely to drive a wave of consolidation in the food industry. Friday’s disclosure followed speculation late last year that Kraft Heinz might make an offer for Mondelez International, the maker of Oreos and Ritz crackers



Shares of Mondelez, and those of companies like General Mills and Campbell Soup that had been seen as potential targets, fell on Friday in part because of disappointment over news of the Unilever bid. Shares of Kraft Heinz surged nearly 11 percent.

The Brazilian principals of 3G have led a buying spree over two decades to become a global force in food and beverages. In doing so, they have won the admiration of no less a business eminence than Mr. Buffett. They took a small Brazilian brewing company and eventually transformed it into Anheuser-Busch InBev, the 800-pound gorilla of beer.