Since its $85-billion bailout by the federal government last September, AIG has sought to sell assets to help repay the loan. These have included business lines as well as some of the company's real estate holdings. In the case of the 15-story building in Tokyo's Marunouchi district, a source says a $1-billion ballpark figure is "a good starting point, although the market will determine the price, of course."

What that price will end up being is difficult to determine, in part because the volume of sales globally has declined since the Wall Street meltdown. Both Cushman & Wakefield and Real Capital Analytics recently reported that commercial property sales transactions declined by 59% in 2008. In particular, Japan's volume, which was down 23% for the year, plummeted 80% in Q4 2008 compared to the same quarter in 2007, according to RCA.

AIG has maintained headquarters in Tokyo since Gen. Douglas MacArthur asked the company to set up shop there to insure his postwar occupation forces. The AIG building was rebuilt in 1975 and recently updated to incorporate earthquake-safety regulations.