The funded status of the 100 biggest public defined benefit pension plans in the U.S. grew by $60 billion in the fourth quarter, the result of robust equity returns in 2017, Milliman Inc., a consulting and actuarial firm, reported Friday.

These plans, which comprise Milliman’s Public Pension Funding Index, had investment returns of 3.2%, with a spread ranging from 1.6% to 4.3%.

The plans’ funded ratio rose to 73.1% from 71.6% in the third quarter.

Milliman noted that strong investment returns during the fourth quarter helped five public pensions cross the 90% funded threshold, bringing the total to 21 that have done so.

Source: Milliman

“While a lot of media attention has been paid to the recent market volatility in early February, it’s not a reason to panic when it comes to public pensions,” Becky Sielman, author of the Milliman index, said in a statement.

“Equity gains and losses are typically smoothed out over a number of years when calculating pension funding, making short-term market volatility less of a concern on funding than, say, interest rate assumptions, which carry greater long-term implications for these pensions.”

A recent report found that retirees are becoming more dependent on financial assets to maintain their standard of living because of the shift in retirement savings from DB pensions to defined contribution plans and because Social Security is expected to replace a smaller share of earnings because of the increase in the full retirement age.

Milliman said the total pension liability of the 100 plans had increased by about $39 billion to an estimated $4.947 trillion at the end of the fourth quarter.

It is expected to grow modestly over time as interest on the TPL and the accrual of new benefits outpace benefits paid to retirees.

According to the report, asset values for the 100 plans have increased from $3.5 trillion to $3.6 trillion quarter over quarter. While investments brought in some $126 billion, the plans collectively paid out about $28 billion more in benefits than they took in from contributions.

— Check out Next Crisis in Finance May Be Public Pensions, PGIM’s Hunt Says on ThinkAdvisor.