BOSTON (AP) -- Officials say the Massachusetts public pension fund lost about 13 percent of its value or about $5 billion last month, but still outperformed similar funds.
  
The Pension Reserves Investment Trust has lost about 27 percent of its value this year and was worth about $40 billion as of Oct. 31.
  
The state Treasurer's Office says the Standard & Poor's 500 stock index fell 17 percent in October and is down 33 percent for the year, while the average large pension fund has lost about 28 percent.
  
Executive Director Mike Travaglini says the fund, which pay for the retirement benefits of many public employees, was saved from deeper losses by its diversity. He says equity portfolios lost 19 percent, but hedge fund and private equity investments lost much less.