The Thrift Savings Plan (TSP) is a retirement savings and investment plan for federal employees.

The purpose of the TSP is to provide supplemental retirement income.

The TSP offers federal employees the same type of savings and tax benefits that many private corporations offer their employees under “401(k)” plans.
In the civilian component of the TSP, employees covered by the Federal Employees’ Retirement System (FERS) and the Civil Service Retirement System (CSRS) can contribute to the TSP. The participation rules are different for FERS and CSRS employees.