5 CFR §892.301

As a participant in premium conversion, instead of having your premium withheld from after-tax salary, your salary will be reduced (through a Federal allotment) by the amount equal to your FEHB premium, which you will allot to your agency. The allotment from salary satisfies the FEHB premium payment requirement of 5 U.S.C. 8906. Your employer is authorized to accept this allotment under § 550.311(a)(7) and § 550.312 of this chapter or, for employers not subject to those regulations, a similar mechanism. Your agency will use the allotment to pay your share of your FEHB premium. This will reduce your taxable income as described in § 892.102.