American International Group Inc. may be nearing the final stages of what would be its largest asset sale yet -- the divestiture of aircraft-leasing subsidiary International Lease Finance Corp. -- which sources say could fetch nearly $5 billion.

Advising the troubled insurance giant are New York boutique bank Moelis & Co. LLC and legal counsel Milbank, Tweed, Hadley & McCloy LLP. A source says International Lease founder, chairman and CEO Steven Udvar-Hazy was behind the Moelis pick.

Ken Moelis' old firm, UBS Investment Bank, is advising on several deals involving the beleaguered AIG. UBS' Alejandro Przygoda and George Matsuzaka, along with legal counsel Willkie Farr & Gallagher LLP, advised Farmers Insurance Group of Cos. on its $1.9 billion acquisition of AIG's car insurance unit, 21st Century Insurance Co., announced in late April. UBS also advised AIG on its sale of Swiss bank AIG Private Bank Ltd., announced in December, to Aabar Investments PJSC of Abu Dhabi. Richard Ginsburg and Peter King of Weil, Gotshal & Manges LLP were legal counsel. UBS also received the mandate to run AIG's auction of its AIG Investments division.

UBS is not the only big bank working on AIG deals. Banc of America Securities LLC, which advised AIG on the 21st Century sale alongside Sidley Austin LLP, was also hired to work on the sale of the insurer's AIG Global Real Estate division, which has $12.4 billion worth of real estate funds. Mark Adley, Richard Casavechia, Anthony Ragozino, Andrew Karp and Patrick O'Connell led the BofA 21st Century team. Adley, who has a decade-long advisory relationship with AIG, was part of the BofA team that advised AIG in May 2007 in its acquisition of the remaining 39.2% it didn't already own in 21st Century.

Blackstone Group LP's Martin Alderson Smith, John Studzinski, Larry Nath and Tom Stoddard are overseeing AIG's entire restructuring. In 1998, AIG made a $1.35 billion long-term investment in Blackstone and its affiliated companies. --Michael Rudnick