Anheuser-Busch owns Budweiser, Michelob and 27% of China's Tsingtao
Anheuser-Busch, the brewer best known for Budweiser, has rejected a $46.3bn (Ł23.3bn) takeover offer from its Belgian-Brazilian rival InBev.
Its board said the offer undervalued the company, but added that it was open to consider any proposals that would provide full value to its shareholders.
Anheuser-Busch's board said the offer also failed to take into account its "Blue Ocean" cost-cutting initiative.
But the company's shares still traded well below the $65 a share offered.
They closed in New York at $61.35 and rose to $61.90 in after-hours trading after the bid was rejected.
InBev is the world's second largest brewer, with brands such as Stella Artois and Beck's, and if the takeover were to be successful it would take over the number one spot from SAB Miller.
There was manoeuvring by InBev during the day that suggested it might be prepared to attempt to bypass Anheuser-Busch's board.
The company filed a case in a Delaware court to confirm the ability of shareholders to remove the current directors.