Tokyo: Embattled insurer American International Group Inc. is close to selling its Japanese headquarters for around $1 billion to help pay off its debt to Washington, the Wall Street Journal said Monday.

The 15-story building will likely be purchased by a Japanese insurance company, though the timing is unclear because of this week’s “Golden Week” holidays, the paper said citing unnamed sources. Financial markets are closed through Wednesday.

The deal would be among the biggest divestitures New York-based AIG has made to reimburse the US government for its massive infusion of aid, according to the Wall Street Journal.

Phone calls to AIG’s Japan headquarters went unanswered Monday.

Although the building is 35 years old, it sits on prime real estate in central Tokyo, next to the Imperial Palace. AIG’s roots in Japan extend back to 1946, and the company is now the country’s biggest foreign casualty insurer.

The US government provided AIG with an $85 billion loan in September. As market conditions worsened and losses piled up at the insurer, the government revised and expanded its loan package to AIG several times. The package of loans now totals nearly $180 billion after being expanded in March when New York-based AIG reported a fourth-quarter loss of $61.7 billion, the largest ever quarterly corporate loss in US history.

As part of the loan package, the government has also taken a roughly 80% stake in the insurance giant.

AIG may also be nearing a deal to unload its airplane leasing business, International Lease Finance Corp., the Wall Street Journal said.