While Ackman's offering documents did not specify the company being targeted, the documents gave enough clues so that those who have seen them feel almost certain it is Anheuser Busch.
Ackman has made a name for himself as an activist by going after brand-name companies. His highest profile battle involved McDonalds. While Ackman failed to get McDonald's to agree to his demands, the stock moved up nicely during his period of agitation and he is credited with having been a catalyst for creating value.
It's not clear how much of the $2 billion Ackman has raised for his latest foray has already been used to buy stock. With a market cap exceeding $40 billion, even a $2 billion position in Anheuser-Busch would be below 5%.
But as Carl Icahn proved in Time Warner and Motorola and Ackman proved in McDonald's, change can still be sought without any chance of a takeover.
At Bud, that change might take the form of a split of the company into its components of brewing, packaging and real estate, which largely takes the form of its theme parks. Ackman's plan is not thought to encompass a balance sheet bust up as much as a simple split already described.
Bud has been the subject of some takeover talks this year and Warren Buffett's Berkshire Hathaway is a significant owner of its shares. The stock has recently been moving up, perhaps because of buying from Ackman and from other hedge funds that tend to mimic his upcoming moves.
At Anheuser Busch, officials declined comment.