Stifel Nicolaus has cut its rating on shares of Anheuser-Busch to "Hold" from "Buy", saying it had made the decision on valuation.

"Valuation was the basis of our upgrade in March, and recent strength makes the shares less compelling, in our estimation, than they were then," its analyst Mark Swartzberg said in a research note.

He added that recently AB shares had rallied on takeout speculation.

"It is possible that a deal is imminent, and comparable transaction multiples yield a reasonable takeout price around $60 per share, by our analysis," the note said.

"However, we have no knowledge of any M&A negotiations or discussions between Anheuser and any other party, are unconvinced a deal is in hand, and generally view takeout potential as an inadequate basis for owning a stock."

Stifel Nicolaus' 12-month fair value estimate remains US$54 per share.