ChemChina and Syngenta have confirmed they have come to terms on a takeover of the Swiss agrochemicals giant by the Chinese state-owned chemical group for a total value of €39.4 billion.

Reports said it would be China’s biggest foreign takeover, more than double the 2012 purchase of Canada’s Nexen by CNOOC for $17.7 billion.

Syngenta’s shares rose on the confirmation but later traded below the takeover offer.

The Swiss company’s interim CEO, John Ramsay, called the takeover arrangement “very appropriate and attractive” to Syngenta’s shareholders. At the same time, however, he said the company’s board would have to consider rival offers if they were made.

Monsanto also has been interested in acquiring the Basel-based company.

Under the terms of the deal, Ramsay said ChemChina, will pay fees of around $3 billion to Syngenta should it fail to meet all the requirements of the transaction, while Syngenta will owe the Chinese company $.5 billion if it is accountable for a breakdown.

“The discussions between our two companies have been friendly, constructive and cooperative,” said ChemChina’s chairman, Ren Jianxin. “We will continue to work alongside the management and employees of Syngenta to maintain the company’s leading edge in the global agricultural technology field.”