Pennsylvania’s biggest pension fund, battered by an ongoing FBI investigation and a deep schism on its board, has announced some good news: Investment returns surged a record 25% in the last fiscal year, boosting the fund’s value to more than $70 billion.

“Enjoy it,” Brian Carl, the PSERS fund’s chief financial officer, told the plan’s board on Friday after detailing the boost for the plan, which pays $6 billion yearly to 250,000 retired teachers and other former public school employees.

The increase, reflective of a booming world economy shaking off COVID-19, was quite a turnaround for the plan. The fund — formally, the Public School Employees’ Retirement System — saw its investments return a profit of only 1.1% the previous fiscal year.

Still, the Pennsylvania system trailed many other public retirement plans. Pensions & Investments, a trade publication, currently lists 20 funds that have reported their returns for the fiscal year. Of them, PSERS trailed 16. The highest rate of return was reported by the system for Oklahoma teachers: 33%. The S&P 500 stock index reported a 38% return for the fiscal year, which ended June 30.

The volunteer PSERS board has been wracked by internal divisions. In June, six of 15 members sought and failed in a push to fire the plan’s executive director and its chief investment officer. The dissidents argued in a detailed letter of complaint that the plan would be worth $80 billion today had its investments done as well as those in the top performing tier among public plans.

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The critics say PSERS is far less reliant on ordinary stocks and bonds than other plans and say it has invested far too much in hedge fund startups and private-equity takeovers mainly notable for their high fees.

The fund has also been awaiting the outcome of an ongoing FBI investigation. In March, federal prosecutors subpoenaed fund records about two apparently disparate matters: the plan’s appropriation of $15 million to buy and improve several buildings and parking lots near its Harrisburg office and the board’s adoption and later disavowal of an exaggerated figure for long-term investment returns.

The botched calculation was a serious error. Under state law, working teachers hired since 2011 have to pay more out of their paychecks into the retirement system when returns fall below certain targets.

PSERS’ board initially said in December that returns had narrowly cleared that threshold. But the panel said in April that number was incorrect. It then adopted a new, and lower, figure, triggering a hike in payment by 100,000 school employees, starting July 1.

The plan started the last fiscal year, on July 1, 2020, with assets worth $59 billion. While figures aren’t yet final, Carl said PSERS expect to value its assets at $70.3 billion as of the start of this fiscal year. Its previous high of $67.5 billon was notched in 2007, just before the so-called Great Recession.

Even with $70 billion in assets, the plan faces a big unfunded gap — $40 billion or so — between its money and what it needs to meet all forecasted obligations. This is so even though both Republican and Democratic governors, with bipartisan legislative support, have taken step to rein in benefits for newly hired educators, reducing checks, making employees work more years, and steering them into 401(k) plans without guaranteed payments.

Court rulings have limited the ability of state government to change the generous benefits given teachers hired in earlier years.

In all, public school employees pay about $1.1 billion into the fund yearly, and taxpayers about $5 billion. The fund says the record return from investments in the last fiscal year poured about $12 billion into the fund.