The New York-listed group, led by boss Hugh Grant, tried to win Syngenta round with a sweetened bid worth 470 Swiss francs a share earlier this month. Syngenta formally spurned the offer yesterday, forcing Monsanto to give up the chase.
The approach is the third time Grant has tried to buy the group, wooing it in 2011 and again in 2012.
“Without a basis for constructive engagement from Syngenta, Monsanto will continue to focus on its growth opportunities built on its existing core business to deliver the next wave of transformational solutions for agriculture,” Monsanto said.
In April, Monsanto had reignited its unrequited interest by bidding 449 Swiss francs a share to win Syngenta into a union – before hiking its offer again earlier this month.
“After engaging with Monsanto on their latest approach, the board unanimously rejected their revised proposal. It significantly undervalued the company and was fraught with execution risk,” Syngenta said.
Syngenta shares dropped as much as 18 per cent yesterday while Monsanto’s stock soared. Monsanto had planned to own 70 per cent of the new group, with Syngenta owning the rest.
The end of the romance will hurt closer to home. Monsanto planned to relocate the new firm’s tax base from the US to the UK – offering a potential boon to Treasury’s coffers.