ChemChina has again extended, this time until Sept. 13, its $43 billion tender offer for all publicly held registered shares of Swiss agrochemicals giant Syngenta as well as all outstanding American depositary shares representing common shares.

This is the second extension for the Chinese company as it awaits regulatory clearance from authorities in the EU and the US – the previous deadline was Jul. 18. The company has reserved the right to extend the deadline again if circumstances require, but said it continues to expect to conclude transaction by end of year.

According to its offer prospectus, ChemChina may continue to extend the main offer period until Nov. 23, if regulatory approval has not been granted, as the terms requires that at least 67% of Syngenta’s shares be tendered for the transaction to conclude.

The toughest scrutiny is expected from the Committee on Foreign Investment in the United States (CFIUS). ChemChina and Syngenta voluntarily initiated a review by CFIUS following their announcement of the proposed merger in February, but the deal faces opposition in the US Congress.