(Reuters) -Mumbai International Airport Ltd, a subsidiary of Adani Airport Holdings, has secured a $750 million investment from a group led by affiliates of Apollo-managed funds and other long-term backers, the U.S. private capital group said on Monday.

The four-year unsecured notes will be used to refinance existing debt, with an option to raise an additional $250 million, Apollo said in a statement.

Adani Airports Holdings, the airport division of Adani Enterprises, secured a $750 million investment earlier this month from a consortium of international banks.

The unit is expected to be spun off and listed by March 2027, according to a Bloomberg report from June.

Adani Airport Holdings currently operates eight airports across India and also oversees the Navi Mumbai International Airport, a strategically located project on the outskirts of Mumbai set become operational soon.

Adani Airport Holdings and Adani Enterprises did not immediately respond to requests for comment outside of business hours.