5 U.S.C. § 8423 — Government contributions

(a) Every agency that has employees or Members covered by this system^* must pay into the Fund^*. The payment has two parts added together: one part covers regular employees, calculated as a set "normal-cost percentage^*" times the total basic pay^* the agency paid those employees; the other part covers Members, Congressional employees, and higher-risk categories like law enforcement officers, firefighters, Supreme Court^* Police, nuclear materials couriers, customs and border protection officers, air traffic controllers, military reserve technicians, and certain CIA retirement-system employees, using their own normal-cost percentage times their total basic pay.

When the Office^* sets these normal-cost percentages, it accounts for what employees already contribute under section 8422. For periods after December 31, 2013, the percentage is calculated as though a particular 2013 budget law provision never passed — meaning agencies pay somewhat more. That extra money goes toward paying down the old Civil Service^* Retirement System's unfunded liability, until the Office determines that liability has been eliminated; after that, this special rule stops applying. It never applies, though, to what the Postal Service and Postal Regulatory Commission pay.

Agencies pay these contributions out of the same funding source they use to pay the employees in question — for elected officials, out of the fund used for other salaries in that office, and for House of Representatives employees, out of the applicable House accounts. Contributions are deposited following procedures the Comptroller General sets.

(b) Separately, the Office calculates the Fund's "supplemental liability^*" every year — the retirement system's shortfall — figuring it once for most people and once for current and former Postal Service and Postal Regulatory Commission employees and their survivors. Each year's shortfall is paid off over 30 equal annual installments, with interest at the rate used in the system's most recent valuation. The Office tells the Secretary of the Treasury the installment amount for the general shortfall, and tells the Postmaster General the installment for the Postal Service's share. The Treasury then credits that amount to the Fund out of general Treasury money, and the Postal Service pays its own share directly to the Fund. To do these calculations, the Office can direct the Civil Service Retirement System's Board^* of Actuaries to run the numbers, or can rely on the Board's most recent work.

(c) If an agency head disagrees with an amount they owe under this section, they can ask for it to be reconsidered, following Office regulations. That request goes to the Board of Actuaries, which reviews the Office's math and can adjust the amount. Whatever the Board decides is final.