The move will help lower the unfunded pension liabilities in the $8 billion Oklahoma Public Employees Retirement System.

The share of Americans in the labor force, known as the participation rate, is hovering around an almost four-decade low as the population ages and discouraged job seekers give up looking for work.

At the end of the third quarter, recordkeepers reported that 18.3 percent of participants had outstanding loans. Before the Great Recession began in 2008, the rate had been 15.3 percent.

Public defined benefit plans, endowments and foundations also lost ground in January as a result of the falling equity markets.