(a) Title requirements. A reemployed annuitant is entitled, on separation, or conversion to intermittent service, to a supplemental annuity if —   (1) The annuitant performed —   (i) At least 1 year of actual, continuous, full-time service;   (ii) Actual, continuous part-time service equivalent to 1 year of actual full-time service; or   (iii) A combination of part-time and full-time actual, continuous service that is equivalent to 1 year of actual full-time service; and   (2)   (i) The annuity is not terminated or suspended on reemployment; and   (ii) The pay during reemployment was subject to offset by the amount of annuity allocable to the period of reemployment; or   (iii) The reemployed annuitant separates from an interim appointment made under the provisions of §772.102 of this chapter.

(b) Computation of supplemental annuity   (1) CSRS.   (i) That portion of a supplemental annuity that is based on the total years and full months of creditable reemployment service performed while covered under CSRS, is computed under the provisions of 5 U.S.C. 8339(a), (b), (d), (e), (h), (i), (n) and (q). Unused sick leave to the reemployed annuitant's credit immediately prior to separation from reemployed annuitant service will be credited under the rules prescribed in §831.302 of this chapter, and 5 U.S.C. 8339(m), not to exceed the amount of unused sick leave available immediately before the effective date of an election of FERS coverage, and not including any unused sick leave included in the computation of an annuity or supplemental annuity the annuitant is receiving at the time of separation from the most recent period of reemployment.   (ii) A supplemental annuity computed in whole or in part under the provisions of this paragraph, using CSRS-Offset service, is subject to reduction under subpart G of this part.   (2) FERS. That portion of a supplemental annuity that is based on the total years and full months of creditable reemployment service performed on and after the effective date of FERS coverage is computed under the provisions of 5 U.S.C. 8415 (a) through (f).   (3) Average pay. The average pay used in the computation of a supplemental annuity is the average basic pay for the entire period of actual continuous reemployment service, excluding intermittent service.   (4) Survivor reduction. If the reemployed annuitant's annuity, at the time he or she applies for supplemental annuity, is reduced to provide a survivor benefit for a spouse, (or, for FERS annuitants only, a former spouse), the supplemental annuity will be reduced by 10 percent, and the survivor annuities increased, if the annuitant was retired under CSRS, by 55 percent of the supplemental annuity, and if the annuitant was retired under FERS, by 50 percent of the supplemental annuity, unless the reemployed annuitant notifies OPM at the time of application that he or she does not wish to have such reductions and increases effected.

(c) Creditable service.   (1) All actual reemployment service performed after the date of retirement on a full-time or part-time basis may be credited in the computation of a supplemental annuity provided —   (i) When the reemployment service was performed on or after October 1, 1982, retirement deductions were withheld or, for CSRS annuitants, a deposit has been paid under the provisions of 5 U.S.C. 8334;   (ii) The reemployment service was not performed subject to another retirement system, except when the deductions under the other retirement system have been refunded and a deposit paid to OPM, where the law so permits, or benefits under the other retirement system have been waived in favor of CSRS or FERS benefits; and   (iii) The reemployment service has not been used in the computation of another supplemental or redetermined annuity.   (2) A period of reemployment service during which annuitant status continues and annuity is paid, and which is excluded from the normal annuity offset from pay by special statutory provision, cannot be credited in the computation of a supplemental annuity or any subsequent annuity entitlement.

(d) Commencing date.   (1) Except as provided in clause (2) of this subparagraph, the supplemental annuity commences on the earlier of the first day of the month following —   (i) The day the annuitant is separated from reemployment; or   (ii) The day the annuitant is converted to an intermittent status.   (2) The supplemental annuity of a FERS annuitant, and the supplemental annuity of a CSRS reemployed annuitant who has not elected FERS coverage and who was —   (i) Involuntarily separated from the reemployment service (except by removal for cause on charges of misconduct or delinquency);   (ii) Involuntarily converted to an intermittent status, or;   (iii) Separated from reemployment service, or converted to intermittent status, after serving 3 days or less in the month of such separation or conversion — shall commence on the earlier of the day after separation from reemployment service, the effective date of conversion to intermittent status, or the day after the date pay ceases.