With one month left in the state’s fiscal year, the public pension fund for Massachusetts workers was up 15.4 percent through the end of May, compared with its benchmark of 13.1 percent. The fund is on track for its best performance since fiscal 2011, when it gained 22.3 percent.
For the calendar year, the fund has gained 4.9 percent, vs. a benchmark of 4.2 percent. It has reached an all-time high of $59.8 billion in assets.
The pension fund’s performance matches almost exactly the 5 percent rise in the Standard & Poor’s 500 Index in that period, even though the retirement assets are spread across an array of asset classes, from bonds and hedge funds to private equity. The Barclays Aggregate Bond index is up 3.9 percent for the calendar year.
The S&P 500 was up 21.4 percent for the fiscal year through May. The pension fund’s best-performing categories in the past year have been private equity, global stocks, and long-term Treasury bonds.
The pension fund in March began buying more Treasuries as a hedge against potential down markets after a big run-up for stocks. But by chance, interest rates have fallen in the past few months, generating large, unexpected gains in bonds for the fund.
The long-duration Treasuries gained nearly 10 percent from March through May.
Beth Healy can be reached at beth.healy@globe.com. Follow her on Twitter @HealyBeth.