More than one-fourth of the 539,000 federal workers eligible to invest up to 15 percent of pay into a new tax-deferred thrift account have signed up for the program since it started in April, according to the Federal Retirement Thrift Investment Board, which manages the program.

The sign-up rate for the 2 million employes hired before 1984, who are limited to investing 5 percent of pay, is believed to be much lower.

As of Monday, the fund was worth $285 million and growing at the rate of more than $1 million a day. That money represents contributions by workers and the government, and earnings on the investments.

Funds designated by payroll deduction are invested daily by the Thrift Board in a so-called G-Fund. It is made up of long-term Treasury securities. The interest rate changes monthly. It is now paying 8 5/8 percent. In May the interest rate was 8 3/8 percent.

The thrift plan is a feature of the new Federal Employees Retirement System, which covers most workers hired since 1984. Workers under the FERS system can make tax-deferred investments of up to 10 percent of salary (or a maximum of $7,000 this year), and get a 5 percent tax-deferred matching contribution from the government.

Workers under the old civil service pension program (mostly people hired before 1984) can invest, but are limited to 5 percent of pay. They do not get any matching contributions from the government unless they switch to the FERS system later this year.

There will be an open season -- from July through the end of December -- when people under the old pension plan can switch to FERS. Those who do will be able to invest more, and get the government match to their investment accounts. Benefits under the old pension plan are based on salary and length of service. Under FERS benefits are a combination of Social Security, a reduced civil service pension and the greater thrift plan investment option.

Starting next year employes under the FERS plan will be able to invest in either the G-Fund, a guaranteed investment fund paying a flat rate of interest, or a higher-risk, higher-reward stock fund. Workers who remain under the old pension plan can invest only in the G-Fund.

To induce employes to come into the new FERS pension plan, the government automatically makes a 1 percent tax-deferred contribution to their thrift plan account, even if they put in nothing.

Thrift board officials said yesterday that, as expected, employes in agencies with higher grade levels (and higher average salaries) were first to take advantage of the new investment program. More than 40 percent of the eligible FERS workers have signed up for the thrift plan at the Department of Energy, Department of Transportation, Enviromental Protection Agency and the Administrative Office of the U.S. Courts. In addition to their high-grade, high-pay levels, all those agencies have done a good job explaining the new thrift plan, and getting information to workers.Job Mart

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