In a statement on 16 September, SABMiller said it had noted recent press speculation about a merger of the two and confirmed that AB InBev had informed it that it intended "to make a proposal to acquire SABMiller". However, it said it had not yet received any proposal.
A new statement on 7 October from SABMiller said its board had met to consider a proposal from AB InBev to acquire it at a price of £42.15 ($64.68) per share, saying it "unanimously rejected" that offer as it "still very substantially undervalues SABMiller, its unique and unmatched footprint, and its standalone prospects".
In addition to in-house teams at both companies, SABMiller is being advised by Finsbury and AB inBev by Brunswick.
SABMiller handed Finsbury the corporate and financial comms brief earlier this year, having previously worked with FTI Consulting.
A spokeswoman for AB InBev told PRWeek by email last week that it was working with Brunswick but declined to expand on the firm's brief, saying: "We do not disclose the agreements we make with our agencies."
The ball is now in AB InBev's court, as it has until Wednesday to make another offer.
A statement from Carlos Brito, AB InBev CEO, on 8 October chided SABMiller, saying: "Notwithstanding our good faith efforts, the board of SABMiller has refused to meaningfully engage with us. Our proposal creates significant value for everybody. How long will it be before shareholders see a value of over GBP 42 in the absence of an offer from AB InBev? If shareholders agree that we should be in proper discussions, they should voice their views and should not allow the board of SABMiller to frustrate this process and let this opportunity slip away."