(WSJ) - $108 billion brewing megadeal needs to be approved by U.S., EU and others.

 Anheuser-Busch InBev NV’s formal agreement to buy SABMiller PLC for about $108 billion sets in motion a complicated, yearlong process of winning regulatory approval around the world.

Wednesday’s announcement brings an end to two months of negotiations between the world’s two largest brewing companies, but many analysts think the hardest work is yet to come.

Together, AB InBev and SABMiller sell more than 30% of the world’s beer—including brands like Budweiser, Stella Artois, Grolsch and Pilsner Urquell. Exane BNP Paribas said the combined company would be the world’s largest consumer-staples maker by earnings before interest, taxes, depreciation and amortization and the third-largest by sales, behind Procter & Gamble Co. and Nestlé SA .

To close the deal, AB InBev will have to win regulatory approval in many places including the U.S., the European Union, China, South Africa, Colombia, Australia and India. Should the acquisition fall apart, AB InBev would have to pay $3 billion to SABMiller.

Just ahead of Wednesday’s announcement, AB InBev succeeded in clearing the most pressing regulatory hurdle with a side deal in the U.S. to sell SABMiller’s 58% stake in the MillerCoors LLC joint venture to Molson Coors Brewing Co. —which holds the remaining stake—as well as the Miller portfolio outside the U.S. for $12 billion.