The Massachusetts state pension fund performed even better than a strong stock market and added nearly $5 billion to its assets in 2012, rebounding from flat investment results the previous year.
The $51.9 billion pension fund posted a gain of 13.9 percent on its investments for last year, state officials said Tuesday. The broad Standard & Poor’s 500 stock index rose 16 percent in 2012. The Pension Reserves Investment Management board, which oversees the state fund, said its return outpaced an internal benchmark by 0.84 percent.
The pension fund invests retirement money for 522,792 retired and active workers with the state and many cities and towns, including teachers.
The fund’s strongest gains came in global stocks, which rose 17.5 percent, as well as in fixed income, private equity, and real estate. And hedge funds, which have been a performance problem for the state in recent years, produced an 8.4 percent gain, well over the 4.8 percent benchmark.
The board’s executive director, Michael Trotsky, called the performance very strong and said the fund’s current mix of assets was sound. Trotsky joined PRIM in 2010 and has been charged with keeping better risk controls at the fund, which plunged nearly 24 percent in the 2008-2009 financial crisis.
In the current environment, pension staff said at a board meeting Tuesday, they plan to take a closer look at their emerging markets managers, as well as bond managers, to be sure they are well positioned in what could become a rocky period for fixed-income investments.
“We’re relatively optimistic on equities and less optimistic on bonds,’’ Trotsky said at the meeting.
The fund has 43 percent of its assets in equities and 19 percent in fixed-income securities; the rest is in alternative investments like hedge funds, private equity, and timber.
Trotsky’s new hire to watch over hedge funds, Eric Nierenberg, spoke at the board meeting for the first time.
He laid out a plan to examine a number of hedge fund firms closely in person, in addition to working with the pension fund’s consultants in the sector.
He also pledged to look harder at fees and to seek alternative investments that provide hedge fund-like returns without taking 20 percent of the profits as well as a fixed 2 percent fee.
Separately, the state fund said it would invest up to $60 million in a new venture capital fund being raised by Battery Ventures in Waltham. The firm’s Fund X is raising $650 million, plus a $250 million side fund.
In addition, the state plans to invest $25 million with Spark Capital, a venture firm started by former Battery partner Todd Dagres.
Correction: Because of a reporting error, an earlier version of this story understated the total return of the Standard & Poor’s 500 Index in 2012. It rose 16 percent.