(a) Except as provided in subsection (c), the amount of the annuity supplement to which an individual is entitled under section 8421 for any month (determined without regard to subsection (c) of such section) shall be reduced by the amount of any excess earnings of such individual which are required to be charged to such supplement for such month, as determined under subsection (b).

(b) The amount of an individual's excess earnings shall be charged to months as follows:

(1)

(A) There shall be charged to each month of a year under subsection (a) an amount equal to the individual's excess earnings (as determined under paragraph (2) with respect to such year), divided by the number of the individual's supplement entitlement months for such year (as determined under paragraph (3)).

(B) Notwithstanding subparagraph (A), the amount charged to a month under subsection (a) may not exceed the amount of the annuity supplement to which the individual is entitled under section 8421 for such month (determined without regard to subsection (c) of such section).

(2) The excess earnings based on which reductions under subsection (a) shall be made with respect to an individual in a year—

(A) shall be equal to 50 percent of so much of such individual's earnings for the immediately preceding year as exceeds the applicable exempt amount for such preceding year; but

(B) may not exceed the total amount of the annuity supplement payments to which such individual was entitled for such preceding year under section 8421 (determined without regard to subsection (c) of such section, and without regard to this section).

(3)

(A) Subject to subparagraph (B), the number of an individual's supplement entitlement months for a year shall be 12.

(B) The number determined under subparagraph (A) shall be reduced so as not to include any month after which such individual ceases to be entitled to an annuity supplement by reason of section 8421(a)(3)(B), relating to cessation of entitlement upon attaining age 62.

(4)

(A) For purposes of this section, and except as provided in subparagraph (B), the "earnings" and the "applicable exempt amount" of an individual shall be determined in a manner consistent with applicable provisions of section 203 of the Social Security Act.

(B) For purposes of this section—

(i) in determining the excess earnings of any individual, only earnings attributable to periods during which such individual was entitled to an annuity supplement under section 8421 shall be considered; and

(ii) any earnings attributable to a period before attaining the applicable retirement age under section 8412(h) shall not be considered in determining the excess earnings of an individual who retires under section 8412(d) or (e), or section 8414(c).

(5) Notwithstanding paragraphs (1) through (4), the reduction required by subsection (a) shall be effective with respect to the annuity supplement payable for each month in the 12-month period beginning on the first day of the seventh month after the end of the calendar year in which the excess earnings were earned.

(c) This section shall not apply to an individual described in section 8412(e) during any period in which the individual, after separating from the service as described in that section, is employed as an air traffic control instructor, or supervisor thereof, under contract with the Federal Aviation Administration, including an instructor or supervisor working at an on-site facility (such as an airport).

(d) The Office shall prescribe regulations under which this section shall be applied in the case of a reemployed annuitant.