The sister agencies have been hired by Bayer to work on the M&A brief from Germany and London, alongside Brunswick, Bayer’s retained agency.
If concluded, the deal would be the biggest takeover by a German company in US history.
News of the bid was confirmed today by Bayer, which has nearly 120,000 staff globally, following a week of speculation.
The offer represents a 37 per cent premium on Monsanto’s $89.03 (£61.52) price per share the day before the offer. Bayer expects the deal to grow its annual revenue from €34.3bn (£26.5bn, $38.4bn) to €47.1bn (£36.4bn, $52.7bn).
Insiders have said it could be the first step in an eventual merger of the two financial PR giants.