Although retirees may not make new investments in the Thrift Savings Plan, those rehired by the government may do so.
A rehired annuitant generally can invest in the TSP under the same terms as any active employee, including eligibility for government contributions if under the FERS program. The annual maximum is $18,500 this year. (Note: Those hired under one of the special authorities allowing receipt of both full pay and an annuity should check their status; in many cases such persons cannot invest in the TSP.)
In addition, “catch-up contributions” to the TSP are allowed for actively employed investors age 50 and above—regardless of whether they have been employed continuously or left for retirement or other purposes and then came back. The dollar limit is $6,000 this year.
For on Reemployed Annuitants Under FERS and CSRS at ask.FEDweek.com
The TSP can only accept investments for the current year; retroactive investments are not allowed.