American International Group Inc is close to selling its Japanese headquarters for about $1 billion and the expected buyer is a Japanese insurance company, the Wall Street Journal reported, citing people familiar with the matter.

With Japanese markets closed for Golden Week holidays until Wednesday, the exact timing of a deal was unclear, the paper said on Monday.

A sale of the AIG's airplane leasing business, International Lease Finance Corp., may also be close, the paper said, citing people with familiar the matter.

(Reporting by Jennifer Robin Raj in Bangalore; Editing by Kim Coghill)