The California Public Employees Retirement System, the world's largest pension fund with over $145bn (€128.4bn) in assets under management, has fired three of its external fund managers over the past few weeks as it seeks to crack down on high fees.

Mark Anson, chief investment officer at Calpers, is seeking to maximise the efficiency of the fund's investment process and has announced a review of costs and fee structures of its external managers across all portfolios.