Government Pension Investment Fund, which oversees the world's largest pool of retirement savings, added Wellington Management Co. to help with active management of foreign-equity investments.

GPIF hired Wellington International Management Co., a unit of the Boston-based company, to assist in managing such investments, according to a statement on its website Monday. The firm will use the MSCI Kokusai Index as its benchmark, the GPIF statement said. Wellington Management, the parent company, had about $774 billion in client assets under management as of June 30.

GPIF held 13 percent of its ¥124 trillion in assets, or ¥16.7 trillion, in international stocks as of Sept. 30, according to its quarterly report. Wellington International joins eight other active foreign-equity managers, including Amundi Japan Ltd. and BNY Mellon Asset Management Japan Ltd., whose selection GPIF announced in a statement on its website on Sept. 2.