Milan owner Silvio Berlusconi and Sino-Europe Sports (SES) had agreed a date of December 13 for the conclusion of a deal that valued the club at 740 million euros (then $825.4 million) and will see Milan join city rivals Inter in falling under Chinese ownership.
On Wednesday SES and Berlusconi's holding company Fininvest agreed on a new date of March 3 following a request by the Chinese consortium, which has already made a first down payment of 100m euros to buy the Serie A giants.
Another instalment of 100m will be paid to Fininvest by December 12, according to a joint statement released by the parties, with the conclusion of the deal set for March 3.
A statement issued by Fininvest said: "Fininvest and Sino-Europe Sports have added an agreement which foresees the conclusion of the sale of AC Milan on March 3.
"The agreement, approved by the administrative board of Fininvest, provides for Sino-Europe Sports to pay a second instalment of 100m euros to Fininvest by December 12.
"The agreement on the extension, which was requested by SES, reiterates that the methods of AC Milan's business operations until the closing date will continue to be based on the principle of shared interests."