Nippon Life Insurance Co. is close to cutting a deal to purchase a building from American International Group Inc. in a prime location in Tokyo, industry sources said Friday.

The agreement, estimated to cost the country's top life insurer around ¥100 billion, may be reached early next week, they said.

The financially distressed U.S. insurance firm has been negotiating the sale of the building with Japanese financial services institutions and real estate companies since February. AIG is trying to sell off its assets as part of its rehabilitation program supervised by the U.S. government.

In the final round of bidding, Nippon Life and a major Japanese property firm offered to buy the building, which is located in Chiyoda Ward and faces the Imperial Palace. Nippon Life is believed to have outbid its rival and is now hammering out the final terms of the purchase, the sources said.

The building houses the Japanese arm of New York-based AIU Insurance Co., an AIG group firm, and various other businesses.

Since the structure is about 35 years old, Nippon Life might rebuild it in the future, the sources said.