UPDATE 1-Calpers posts 2.4 pct loss, Calstrs down 3.7 pct

(Adds results from Calstrs)

SAN FRANCISCO, July 18 (Reuters) - Calpers, the biggest U.S. pension fund, posted a 2.4 percent loss in its June-ended fiscal year, fueled by a 10.7 percent decline in the value of its stock holdings, its top investment officer said on Friday.

Separately, sister pension fund Calstrs reported a 3.7 percent loss in the June-ended year, marking its first loss in six years, also rooted in its stock holdings.

Calpers' 2.4 percent loss marked the worst performance for the fund, the California Public Employees' Retirement System, since its 2002 fiscal year, when it lost 5.9 percent, and reduced the value of its total assets to $239.2 billion at the end of June, said fund spokeswoman Pat Macht.

As of July 16, Calpers' assets were valued at $230.2 billion.

"It was difficult for any investor to make positive returns in stocks this past year, but we realized gains in other areas, ending the year in good financial shape," said Anne Stausboll, the pension fund's interim chief investment officer.

"Private equity returns led the way in gains. Fixed income and our new inflation-linked asset class were also in positive territory," she added.

The fund's inflation-linked asset class includes commodities and infrastructure, investment areas new to Calpers. Russell Read, who recently left as chief investment officer of Calpers to start a green-focused investment firm, had pressed the fund to move into those areas.

Stausboll noted other moves last year that helped limit losses: "Last fall, we underweighted public stocks, and it played a role in moderating the negative impact of equity returns on our fund."