April 15 (Bloomberg) -- The California Public Employees’ Retirement System, the largest U.S. pension, paid Wall Street firms almost $1.2 billion last fiscal year to manage investments, up 20 percent from a year earlier.

Calpers said fees paid to external firms for performance more than doubled in the year that ended June 30 to $377.6 million, up from $165 million the previous year, according to a report released yesterday. Base fees declined 2 percent to $790.5 million. The fund had $285.8 billion under management as of April 14.

Calpers earned 13.2 percent last fiscal year, almost double the 7.5 percent it said it needs each year to cover the costs of benefits promised to retirees. After losing almost a quarter of its value in 2009, the fund has made 3.5 percent in the five years that ended June 30.