The $9.5 billion Western Australia-based GESB has appointed Fidelity, Edinburgh Partners and Sarasin & Partners as new managers in its $2.5 billion international equities portfolio.

GESB made the appointments following a review of its external managers and is focused on ensuring that a diversified mix of styles and processes are used to manage its international equity portfolio, which constitutes one quarter (26 per cent) of the fund's multi-billion investment portfolio it manages on behalf of 310,000 members.

Sharon Hicks, chief investment officer of GESB, said, "Each of the new managers brings different style characteristics that we want exposure to in the portfolio.

"This diversity will afford us the flexibility to optimise our style exposures, ensuring we can remain responsive to the market and deliver sound investment returns over the long term for our members," said Hicks.

The appointments bring the total number of international equities managers to eight, with GMO, Lazard, Genesis Investment Management, Newton Investment Management and State Street Global Advisors already on the roster.