The nation's second-largest public pension fund, the California State Teachers' Retirement System, suffered an estimated 3.7% loss for the fiscal year ended in June, joining the swelling ranks of public plans experiencing their worst returns in six years.

The fund's performance was dragged down by a 13.4% loss in the US stock portfolio, and a 5.8% loss in foreign stocks, according to estimates from Calstrs chief investment officer Christopher Ailman.