The annuity of an individual under section 231a(a)(1) of this title shall be in an amount equal to the amount (before any reduction on account of age and before any deductions on account of work) of the old-age insurance benefit or disability insurance benefit to which such individual would have been entitled under the Social Security Act [42 U.S.C. 301 et seq.] if all of his or her service as an employee after December 31, 1936, had been included in the term “employment” as defined in that Act.

For purposes of this subsection, individuals entitled to an annuity under section 231a(a)(1)(ii) of this title shall, except for the purposes of recomputations in accordance with section 215(f) of the Social Security Act [42 U.S.C. 415(f)], be deemed to have attained retirement age (as defined by section 216(l) of the Social Security Act [42 U.S.C. 416(l)]). For purposes of this subsection, individuals entitled to an annuity under paragraph (iv) or (v) of section 231a(a)(1) of this title shall be deemed to be entitled to a disability insurance benefit under section 223 of the Social Security Act [42 U.S.C. 423].

If an individual entitled to an annuity under section 231a(a)(1)(i) or (iii) of this title on the basis of less than ten years of service is entitled to a benefit under section 202(a), section 202(b), or section 202(c) of the Social Security Act [42 U.S.C. 402(a), (b), (c)] which began to accrue before the annuity under section 231a(a)(1)(i) or (iii) of this title, the annuity amount provided such individual under this subsection, shall be computed as though the annuity under this subchapter began to accrue on the later of (A) the date on which the benefit under section 202(a), section 202(b), or section 202(c) of the Social Security Act began, or (B) the date on which the individual first met the conditions for entitlement to an age reduced annuity under this subchapter other than the conditions set forth in sections 231a(e)(1) and 231a(e)(2) of this title and the requirement that an application be filed.

The amount of the annuity of an individual provided under subsection (a) shall be increased by an amount equal to seven-tenths of 1 per centum of the product which is obtained by multiplying such individual’s “years of service” by such individual’s “average monthly compensation” as determined under this subsection. The annuity amount payable to the individual under this subsection shall be reduced by 25 per centum of the annuity amount computed for such individual under subsection (h)(1) or (h)(2), and subsection (h)(5), of this section without regard to section 231f(c)(1) of this title. An individual’s “average monthly compensation” for purposes of this subsection shall be the quotient obtained by dividing by 60 such individual’s total compensation for the 60 months, consecutive or otherwise, during which such individual received that individual’s highest monthly compensation, except that no part of any month’s compensation in excess of the maximum amount creditable for any individual for such month under subsection (j) of this section shall be recognized. In determining the months of compensation to be used for purposes of this subsection, the total compensation reported for the individual under section 231h of this title or credited to such individual under subsection (j) of this section for a year divided by the number of months of service credited to such individual under subsection (i) of this section with respect to such year shall be considered the monthly compensation of the individual for each month of service in any year for which records of the Board do not show the amount of compensation paid to the individual on a monthly basis. If the “average monthly compensation” computed under this subsection is not a multiple of $1, it shall be rounded to the next lower multiple of $1.

If, in the case of an individual whose annuity under section 231a(a)(1) of this title began to accrue prior to January 1, 1983, the annuity (before any reduction due to such individual’s entitlement to a monthly insurance benefit under the Social Security Act [42 U.S.C. 301 et seq.] and disregarding any amount provided by subsection (h) of this section) plus the supplemental annuity to which such individual is entitled for any month under this subchapter, together with the annuity, if any, of the spouse of such individual (before any reduction due to such spouse’s entitlement to a wife’s or husband’s insurance benefit under the Social Security Act and disregarding any amount provided by section 231c(e) of this title), before any reductions under the provisions of section 231a(f) of this title is less than the total amount which would have been payable to such individual and his spouse for such month, on the basis of the individual’s compensation and years of service, under the provisions of the Railroad Retirement Act of 1937 as in effect on December 31, 1974 [45 U.S.C. 228a et seq.], disregarding, for purposes of the computations under such Railroad Retirement Act of 1937 compensation for any month after December 31, 1974, in excess of one-twelfth of the maximum annual taxable “wages” (as defined in section 3121 of the Internal Revenue Code of 1986 [26 U.S.C. 3121]) for the calendar year 1974, the annuity of such individual and the annuity of such spouse, if any, shall be increased proportionately so as to equal such total amount. For the purpose of computing amounts under this subdivision, the Board shall have the authority to approximate the effect of the reductions prescribed by sections 3(a)(2) and 3(a)(3) of the Railroad Retirement Act of 1937 [45 U.S.C. 228c(a)(2), (a)(3)]. For purposes of computing amounts payable under the Railroad Retirement Act of 1937, any increases in the amounts determined under the first proviso of section 3(e) of such Act which would have become effective after December 31, 1974, shall be disregarded.

If for any month in which an annuity accrues and is payable under this subchapter the annuity to which an individual is entitled under this subchapter (or would have been entitled except for a reduction pursuant to a joint and survivor election), together with the annuity, if any, of the spouse and divorced wife of such individual, is less than the total amount, or the additional amount, which would have been payable to all persons for such month under the Social Security Act [42 U.S.C. 301 et seq.] if such individual’s service as an employee after December 31, 1936, were included in the term “employment” as defined in that Act, the annuities of the individual and spouse shall be increased proportionately to such total amount, or such additional amount: Provided, however, That if an annuity accrues to an individual or a spouse for a part of a month, the amount payable for such part of a month under this subdivision shall be one-thirtieth of the amount payable under this subdivision for an entire month, multiplied by the number of days in such part of a month. For purposes of this subdivision, (i) persons not entitled to an annuity under section 231a of this title shall not be included in the computation under this subdivision except a spouse who could qualify for an annuity under section 231a(c) of this title if the individual from whom the spouse’s annuity under this subchapter would derive had attained age 60 or 62, as the case may be, and such individual’s children who meet the definition as such contained in section 216(e) of the Social Security Act [42 U.S.C. 416(e)]; (ii) after an annuity has been certified for payment and this subdivision was inapplicable after allowing for any waiting period under section 223(c)(2) of the Social Security Act [42 U.S.C. 423(c)(2)], and after having considered the inclusion of all persons who were then eligible for inclusion in the computation under this subdivision, or was then applicable but later became inapplicable, any recertification in such annuity under this subdivision shall not take into account persons not entitled to an annuity under section 231a of this title except a spouse who could qualify for an annuity under section 231a(c) of this title when she attains age 60 or 62, as the case may be, if the individual from whom the spouse’s annuity would derive had attained age 60 or 62, as the case may be, and who was married to such individual at the time he applied for his annuity; and (iii) in computing the amount to be paid under this subdivision the only benefits under title II of the Social Security Act [42 U.S.C. 401 et seq.] which shall be considered shall be those to which the persons included in the computation are entitled.

Effective with the date of any increase after January 31, 1984, in monthly insurance benefits under the Social Security Act [42 U.S.C. 301 et seq.] which occurs, or which would have occurred had there not been a general benefit increase under that Act, pursuant to the automatic cost-of-living provisions of section 215(i) of that Act [42 U.S.C. 415(i)], that portion of the annuity of an individual which is computed under subsection (b) of this section shall, if such individual’s annuity under section 231a(a)(1) of this title began to accrue on or before the effective date of a particular increase under this subdivision, be increased by 32.5 per centum of the percentage increase in the index which is used, or which would have been used had there not been a general benefit increase under the Social Security Act, in increasing benefits under the Social Security Act pursuant to the automatic cost-of-living provisions of section 215(i) of that Act. Any increase under this subsection shall not be deferred and shall be reflected in all payments made to annuitants after such increase under this subsection becomes effective.

The first and, if necessary, the following time or times after January 1, 1983, that monthly insurance benefits under section 202 of the Social Security Act [42 U.S.C. 402] are increased, that portion of the annuity of an individual which is computed under subsection (b) of this section as increased under subdivision (1) of this subsection shall, if such individual’s annuity under section 231a(a)(1) of this title began to accrue in or before the year in which such first increase under the Social Security Act [42 U.S.C. 301 et seq.] became effective, be reduced by the dollar amount by which that portion of the annuity provided such individual under subsection (a) of this section was increased, after any reduction under subsection (m) of this section, as a result of such increase or increases under the Social Security Act until the total dollar amount of such reduction or reductions equals 5 per centum of the annuity amount provided such individual under subsection (a), as reduced under subsection (m), prior to such first increase. In no case shall the reduction by reason of this paragraph operate to reduce such portion to an amount less than $10.

The amount of the annuity provided under subsections (a) and (b) of this section of an individual who (A) will have (i) rendered service as an employee to an employer, or as an employee representative, during the calendar year 1974, or (ii) had a current connection with the railroad industry on December 31, 1974, or at the time his annuity under section 231a(a)(1) of this title began to accrue, or (iii) completed twenty-five years of service prior to January 1, 1975, and (B) will have (i) completed ten years of service prior to January 1, 1975, and (ii) been permanently insured under the Social Security Act [42 U.S.C. 301 et seq.] on December 31, 1974, shall be increased by an amount equal to the amount by which (C) the sum of (i) the primary insurance amount to which such individual would have been entitled, upon the attainment of age 65 (or, if later, for January 1975), under the provisions of the Social Security Act as in effect on December 31, 1974, if his service as an employee after December 31, 1936, and prior to January 1, 1975, were included in the term “employment” as defined in that Act and if he had no wages or self-employment income under that Act other than wages derived from such service as an employee, and (ii) the primary insurance amount to which such individual would have been entitled, upon the attainment of age 65 (or, if later, for January 1975), under the provisions of the Social Security Act as in effect on December 31, 1974, on the basis of his wages and self-employment income derived from employment and self-employment under that Act prior to January 1, 1975, exceeds (D) the primary insurance amount to which such individual would have been entitled, upon the attainment of age 65 (or, if later, for January 1975), under the provisions of the Social Security Act as in effect on December 31, 1974, on the basis of his wages and self-employment income derived from employment and self-employment under that Act prior to January 1, 1975, and on the basis of compensation derived from service as an employee after December 31, 1936, and prior to January 1, 1975, if such service as an employee had been included in the term “employment” as defined in that Act.

The amount of the annuity provided under subsections (a) and (b) of this section to an individual who (A) will not have met the conditions set forth in subclause (i), (ii), or (iii) of clause (A) of subdivision (1) of this subsection, but (B) will have (i) completed ten years of service prior to January 1, 1975, and (ii) been permanently insured under the Social Security Act [42 U.S.C. 301 et seq.] as of December 31 of the calendar year prior to 1975 in which he last rendered service as an employee to an employer, or as an employee representative, shall be increased by an amount equal to the amount by which (C) the sum of (i) the primary insurance amount to which such individual would have been entitled, upon the attainment of age 65 (or, if later, for January 1975), under the provisions of the Social Security Act as in effect on December 31, 1974, if his service as an employee after December 31, 1936, and prior to January 1, 1975, were included in the term “employment” as defined in that Act and if he had no wages or self-employment income under that Act other than wages derived from such service as an employee, and (ii) the primary insurance amount to which such individual would have been entitled, upon the attainment of age 65 (or, if later, for January 1975), under the provisions of the Social Security Act as in effect on December 31, 1974, on the basis of his wages and self-employment income derived from employment and self-employment under that Act as of December 31 of the calendar year prior to 1975 in which he last performed service as an employee under this subchapter, exceeds (D) the primary insurance amount to which such individual would have been entitled, upon the attainment of age 65 (or, if later, for January 1975), under the provisions of the Social Security Act as in effect on December 31, 1974, on the basis of his wages and self-employment income derived from employment and self-employment under that Act as of December 31 of the calendar year prior to 1975 in which he last performed service as an employee under this subchapter and on the basis of compensation derived from service as an employee after December 31, 1936, and prior to January 1, 1975, if such service as an employee had been included in the term “employment” as defined in that Act.

The amount of the annuity provided under subsections (a) and (b) of this section of an individual who (A) will have (i) rendered service as an employee to an employer, or as an employee representative, during the calendar year 1974, or (ii) had a current connection with the railroad industry on December 31, 1974, or at the time his annuity under section 231a(a)(1) of this title began to accrue, or (iii) completed twenty-five years of service prior to January 1, 1975, and (B) will have completed ten years of service prior to January 1, 1975, and is the wife, husband, widow, or widower of a person who will have been permanently insured under the Social Security Act [42 U.S.C. 301 et seq.] on December 31, 1974, shall be increased by an amount equal to the smaller of (C) the wife’s, husband’s, widow’s, or widower’s insurance benefit to which such individual would have been entitled, upon attaining age 65 (or, if later, for January 1975), under the provisions of the Social Security Act as in effect on December 31, 1974, on the basis of such person’s wages and self-employment income derived from employment and self-employment under that Act prior to January 1, 1975, or (D) the primary insurance amount to which such individual would have been entitled upon attaining age 65 (or, if later, for January 1975), under the provisions of the Social Security Act as in effect on December 31, 1974, on the basis of such individual’s wages and self-employment income derived from employment and self-employment under that Act prior to January 1, 1975, and on the basis of compensation derived from service as an employee after December 31, 1936, and prior to January 1, 1975, if such service as an employee had been included in the term “employment” as defined in that Act.

The amount of the annuity provided under subsections (a) and (b) of this section of an individual who (A) will not have met the conditions set forth in subclause (i), (ii), or (iii) of clause (A) of subdivision (3) of this subsection, but (B) will have completed ten years of service prior to January 1, 1975, and is the wife, husband, widow, or widower of a person who will have been permanently insured under the Social Security Act [42 U.S.C. 301 et seq.] as of December 31 of the calendar year prior to 1975 in which such individual last rendered service as an employee to an employer, or as an employee representative, shall be increased by an amount equal to the smaller of (C) the wife’s, husband’s, widow’s, or widower’s insurance benefit to which such individual would have been entitled, upon attaining age 65 (or, if later, for January 1975), under the provisions of the Social Security Act as in effect on December 31, 1974, on the basis of such person’s wages and self-employment income derived from employment and self-employment under that Act as of December 31 of the calendar year prior to 1975 in which such individual last performed service as an employee under this subchapter or (D) the primary insurance amount to which such individual would have been entitled upon attaining age 65 (or, if later, for January 1975), under the provisions of the Social Security Act as in effect on December 31, 1974, on the basis of such individual’s wages and self-employment income derived from employment and self-employment under that Act as of December 31 of the calendar year prior to 1975 in which such individual last performed service as an employee under this subchapter and on the basis of compensation derived from service as an employee after December 31, 1936, and prior to January 1, 1975, if such service as an employee had been included in the term “employment” as defined in that Act.

The amount computed under subdivision (1), (2), (3), or (4) of this subsection shall be increased by the same percentage, or percentages, as benefits under the Social Security Act [42 U.S.C. 301 et seq.] are increased, or would have been increased had there been no general benefit increases under the Social Security Act, pursuant to the automatic cost-of-living provisions of section 215(i) of that Act [42 U.S.C. 415(i)] during the period from January 1, 1975, to the earlier of the date on which the individual’s annuity under section 231a(a)(1) of this title began to accrue or January 1, 1982.

No amount shall be payable to an individual under subdivision (3) or (4) of this subsection unless the entitlement of such individual to such amount had been determined prior to August 13, 1981.

The “years of service” of an individual shall include all his service subsequent to December 31, 1936.

The “years of service” of an individual shall also include his voluntary or involuntary military service, within or without the United States, during any war service period: Provided, however, That such military service shall be included only if, prior to the beginning of his military service and in the same calendar year in which such military service began, or in the next preceding calendar year, the individual rendered service for compensation to an employer or to a person service to which is otherwise creditable under this subchapter, or lost time as an employee for which he received remuneration, or was serving as an employee representative: Provided further, That such military service shall be included only subject to and in accordance with the provisions of subdivisions (1) and (3) of this subsection in the same manner as though military service were service rendered as an employee: And provided further, That such military service rendered after December 1956 shall not be included with respect to any month if (A) any benefits are payable for that month under the Social Security Act [42 U.S.C. 301 et seq.] on the basis of such individual’s wages and self-employment income, (B) such military service was included in the computation of such benefits, and (C) the inclusion of such military service in the computation of such benefits resulted (for that month) in benefits not otherwise payable or in an increase in the benefits otherwise payable: And provided further, That an individual who entered military service prior to a war service period shall not be regarded as having been in military service in a war service period with respect to any part of the period for which he entered such military service.

The “years of service” of an individual who was an employee on August 29, 1935, shall, if the total number of his “years of service” as determined under subdivisions (1) and (2) is less than thirty, also include his service prior to January 1, 1937, but not so as to make his total years of service exceed thirty: Provided, however, That with respect to any such individual who rendered service to any employer subsequent to December 31, 1936, and who on August 29, 1935, was not an employee of an employer conducting the principal part of its business in the United States, no greater proportion of his service rendered prior to January 1, 1937, shall be included in his “years of service” than the proportion which his total compensation (without regard to any limitation on the amount of compensation otherwise provided in this subchapter) for service subsequent to December 31, 1936, rendered anywhere to an employer conducting the principal part of its business in the United States or rendered in the United States to any other employer bears to his total compensation (without regard to any limitation on the amount of compensation otherwise provided in this subchapter) for service rendered anywhere to an employer subsequent to December 31, 1936. Where the “years of service” include only part of the service prior to January 1, 1937, the part included shall be taken in reverse order beginning with the last calendar month of such service.

Where for any calendar year after 1984 an individual has performed service for compensation in less than twelve months of the calendar year but has received compensation in excess of an amount determined by multiplying the number of months in the year in which such individual performed service for compensation by an amount equal to one-twelfth of the current maximum annual taxable “wages” as defined in section 3121 of the Internal Revenue Code of 1986 [26 U.S.C. 3121], the individual shall be deemed to have rendered service for compensation in that number of months in the calendar year, but not to exceed twelve, which is equal to the quotient of the amount of such individual’s compensation for the calendar year divided by an amount equal to one-twelfth of the current maximum annual taxable “wages” as defined in section 3121 of the Internal Revenue Code of 1986, with any remainder produced by this computation increasing the quotient by one, but an individual shall not be deemed under this subdivision to have rendered service for compensation in any month in which such individual was neither in an employment relation to one or more employers nor an employee representative.

Except as provided in subdivision (2) of this subsection, if an annuity awarded under section 231a(a)(1)(iii) of this title or under section 231a(c)(2) of this title is increased or decreased either by a change in the law or by a recomputation, the reduction on account of age in the amount of such increase or decrease shall be computed as though such increased or decreased annuity amount had been in effect for and after the month in which the annuitant first became entitled to such annuity under section 231a(a)(1)(iii) or section 231a(c)(2) of this title.

The reduction required under section 231a(a)(1)(iii) or section 231a(c)(2) of this title may be applied separately to each of the annuity amounts computed under subsections (a), (b), and (h) of this section and subsections (a), (b), and (e) of section 231c of this title. For this purpose, in any case in which an annuity amount was computed for an individual under the provisions of this subchapter or of Public Law 93–445 prior to October 1, 1981, an annuity amount computed under subsections (a), (b), (c), (d) and (h) of this section, subsection (a), (b), or (e) of section 231c of this title, and section 204 or section 206 of Public Law 93–445 shall be reduced by its proportionate share of the reduction on account of age. For purposes of the preceding sentence, annuity amounts computed for an individual under subsections (b), (c), and (d) of this section prior to October 1981 shall be considered as one annuity amount.