Federal Employees Retirement System

The Federal Employees' Retirement System (FERS) is the retirement system for employees within the United States civil service. FERS became effective January 1, 1987, to replace the Civil Service Retirement System (CSRS) and to conform federal retirement plans in line with those in the private sector.

FERS consists of three major components:

• The FERS annuity, a defined benefit plan,
• Mandatory participation in Social Security (most CSRS employees are not part of Social Security and do not pay taxes into the system, nor are they eligible for benefits unless they qualify under private sector employment or by being rehired and covered as CSRS with a Social Security Offset), and
• The Thrift Savings Plan (TSP), a defined contribution plan which operates like a 401(k).