Not all types of federal compensation can be invested in the TSP. Instead, investments must come from “basic pay,” which is defined as the amount of pay based on the rate fixed by law or administrative action for the position held by an employee and is the same as basic pay for federal civilian retirement purposes.

The following elements of pay are included in the determination of basic pay for TSP purposes:

• Locality-based comparability pay as authorized by 5 U.S.C. 5304

• Environmental and night differentials for wage employees (5 U.S.C. 4343(c)(4) and 4343(f))

• Premium pay for standby time under 5 U.S.C. 5545(c)(1)

• Premium pay for law enforcement officers (5 U.S.C. 5545(c)(2), i.e., admin uncontrollable overtime)

• Availability pay (LEAP) for criminal investigators as authorized by 5 U.S.C. 5545a

• Physicians’ comparability allowance as authorized by 5 U.S.C. 5948

• Overtime compensation for customs officers as authorized by 5 U.S.C. 8331(3)(G)

• Additional compensation paid to employees serving in the Republic of Panama (22 U.S.C. 3657)


The following elements of pay and types of payments are not basic pay for TSP purposes:

• Other overtime pay

• Awards, bonuses, and allowances (includes danger pay)

• Foreign and domestic post differential for general schedule, and foreign post differential for wage employees

• Severance pay

• Retroactive pay granted to a retired or deceased employee pursuant to a wage survey

• Lump-sum payment for leave, and Voluntary separation incentive payment (buyout)

• Workers’ compensation payments from the Office of Workers’ Compensation Programs

• Sunday, holiday and military pay

• Supervisory differentials

• Night differentials for GS employees