Shares in the Swiss agrichemical giant Syngenta soared 11%, as US regulators cleared the way for its acquisition by China National Chemical Corp.
The $43bn takeover deal has been cleared by the Committee on Foreign Investment in the United States (CFIUS).
If completed, the deal would be the biggest ever foreign acquisition by a Chinese sate-owned company.
The CFIUS has the power to block investments from overseas interests, if it perceives a security issue, and there were concerns that the body might reject Chinese state ownership of Syngenta, which does about a quarter of its business in the United States.
The deal will still have to be approved by anti-trust regulators, in the US and elsewhere, ChemChina and Syngenta said in a joint statement.
"Both companies are working closely with the regulatory agencies involved and discussions remain constructive," "The proposed transaction is expected to close by the end of the year."
Shares in Syngenta soared on the news, trading up 10.9% in afternoon deals, at 422.10 Swiss francs ($438.10), reflecting the depth of concern that there was before the CFIUS approval.
The ChemChina offer values the company at $465 (447.70 Swiss francs) a share, plus an additional dividend of 5 Swiss francs a share.
Syngenta rejected a bid from the agribusiness giant Monsanto in August 2015, worth 470 Swiss francs in cash and shares.
Syngenta shares reached as high as 428.50 Swiss francs in morning deals, but remains below the record highs touched in the spring of 2015, when Monsanto first began its pursuit of Syngenta.