Swiss pesticide maker Syngenta is a target of China National Chemical Corp., otherwise known as ChemChina.
According to people with knowledge of the matter, ChemChina's 41.7 billion franc ($42 billion) offer has been rejected by Syngenta because of regulatory risk. A takeover would be the largest by a Chinese company of a European target.
Syngenta is said to be talking to other potential suitors. Earlier this year it spurned a $47 billion takeover approach from Monsanto, the world's largest seeds company.