Japan's Government Pension Investment Fund plans to boost investment in growth stocks to increase returns and may eventually allocate several trillion yen to such equities, the Nikkei newspaper said.

The state-run ¥121 trillion ($1.24 trillion) fund, the world's biggest manager of retirement savings, will initially invest several billion yen in a new domestic index focused on returns on equity, governance and trading volume, Nikkei said Saturday without citing anyone.

Japan Exchange Group Inc. will this year announce criteria and about 500 stocks for the new index, which will be based on fundamentals, CEO Atsushi Saito said in Tokyo on July 30. That will be a departure from benchmarks like the Topix index, which includes all stocks listed on the Tokyo Stock Exchange's first section, or the Nikkei 225 Stock Average.