5 CFR 1600.13: Effect of transfer to FERS.

(a) If an employee appointed to a position covered by CSRS elects to transfer to FERS, the employee may make a contribution election at any time.

(b) [Reserved]

(c) If the employee had elected to make TSP contributions while covered by CSRS, the election continues to be valid until the employee makes a new valid election.

(d) Agency automatic (1%) contributions for all employees covered under this section and, if applicable, agency matching contributions attributable to employee contributions must begin the same pay period that the transfer to FERS becomes effective.