Nippon Life Insurance Co., reversing its focus on the domestic market, is planning to invest up to ¥1.5 trillion in mergers and acquisitions overseas over the next three years, sources close to the matter said Friday.

The leading life insurer will aim to triple its profit from business areas other than domestic life insurance to ¥30 billion at the end of a new three-year business plan running through March 2018, the sources said.

Nippon Life has been careful about expanding its operations abroad but is now gunning to regain its status as Japan's No. 1 in terms of premium revenues, an honor taken by Dai-ichi Life Insurance Co. for the first time in the April-September half last year.

Amid concerns the domestic market will shrink along with the population, Nippon Life is eager to buy life insurance and asset management companies in the United States and emerging countries, the sources said.

It will increase its capital by ¥1 trillion to around ¥5.2 trillion by fiscal 2017, they said.

At home, it will promote insurance products for the young and over-the-counter sales at banks, they said.

To bolster its profitability, the insurer also plans to invest in or extend loans to projects in areas with growth potential, such as sectors related to infrastructure-building and the environment, the sources said.

Dai-ichi Life has also been trying to increase its revenues by acquiring midsize U.S. life insurers and through other measures.