Workers who invested in the stock market option of their tax-deferred thrift savings plan lost 4.77 percent over the 12-month period ending in August.

Those whose payroll deduction contributions were earmarked for the TSP's bond market option earned 5.99 percent over the 12-month period. Workers who invested in the steady, but unsexy treasury securities option earned 8.69 percent during the 12-month period.

In August the C-Fund (stock market option) lost 8.65 percent. The F-Fund (bond market option) lost 1.42 percent. The G-Fund (treasury securities) earned 0.72 percent for the month.

The TSP is an optional part of the government's pension program. It is almost identical to 401 (k) plans offered to many private sector workers. Workers who are covered by the new Federal Employees Retirement System can invest 10 percent of their own money, and get a 5 percent match into their accounts from their agencies. All contributions and earnings are tax-deferred. Employees under the old Civil Service Retirement System can invest 5 percent of pay but do not get matching government contributions.

Currently, most employee contributions -- and all government contributions -- go into the G-Fund, which as of Friday was worth $6.8 billion. The C-Fund had a value of $105 million and the F-Fund was worth $45 million.

Beginning with the November open enrollment period, all investment restrictions will end. That means people can put their contributions -- plus government contributions -- into any or all of the funds.Retirement Handbook

Being "with" the government doesn't end with retirement. Workers and retirees share the same health benefits package. What happens to workers' perks can affect retirees.

Congress is constantly tinkering with federal fringe benefits, and not always for the better. To help people plan for retirement, and cope once they have retired, there is a new 170-page handbook for federal and postal people called "Your Retirement." Bill Olcheski, former editor of the Federal Times newspaper, and himself a new federal retiree, wrote it. The book explains life insurance, Social Security, survivor benefits, taxes and thrift savings plan rules. It costs $9.95. For copies or information write: Your Retirement, Dept. WP, P.O. Box 7528, Falls Church, Va. 22040.

Very Public Affair

Government media and public affairs offices are watching the squabble between Housing Secretary Jack Kemp and the office of Sen. Barbara A. Mikulski (D-Md.). It has resulted in language in an appropriation bill that, if it sticks, would wipe out the Department of Housing and Urban Development's public affairs office, and forbid it to relocate and operate elsewhere in the department.

An official of the National Association of Government Communicators called the action a "childish attempt to stick it to Jack Kemp" and a "chilling message" to other government public affairs offices whose bosses displease powerful politicians.