China National Offshore Oil Corp. in July offered to take over Nexen for $15 billion. Nexen announced in December that Canadian Industry Minister Christian Paradis approved of the takeover proposal, ending the Canadian approval process.
"Either party may, except in certain circumstances, extend the Outside Date (of the agreement) from time to time if the required regulatory approvals have not been obtained, provided that in aggregate such extensions shall not exceed 75 business days from January 31, 2013," Nexen said in a statement.
Both companies in November reissued a voluntary request to the U.S. Committee on Foreign Investment to examine CNOOC's proposed takeover. The U.S. government needs to review the deal because Nexen has operations in the U.S. waters of the Gulf of Mexico.
The Canadian government has sought to add diversity to an oil sector dependent on the U.S. market. U.S. officials have expressed concern about the CNOOC deal, saying it could equate to a major U.S. wealth transfer.