For the purpose of this section—

(1) the term “base quarter”, as used with respect to a year, means the calendar quarter ending on September 30, of such year; and

(2) the price index for a base quarter is the arithmetical mean of such index for the 3 months comprising such quarter.

Except as provided in subsection (c) of this section, effective December 1 of each year, each annuity payable from the Fund having a commencing date not later than such December 1 shall be increased by the percent change in the price index for the base quarter of such year over the price index for the base quarter of the preceding year in which an adjustment under this subsection was made, adjusted to the nearest ⅒ of 1 percent.

Eligibility for an annuity increase under this section is governed by the commencing date of each annuity payable from the Fund as of the effective date of an increase, except as follows:

The first increase (if any) made under subsection (b) of this section to an annuity which is payable from the Fund to an employee or Member who retires, to the widow, widower, or former spouse,[1] of a deceased employee or Member, or to the widow, widower, former spouse, or insurable interest designee of a deceased annuitant whose annuity has not been increased under this subsection or subsection (b) of this section, shall be equal to the product (adjusted to the nearest ⅒ of 1 percent) of—

(A) 1⁄12 of the applicable percent change computed under subsection (b) of this section, multiplied by

(B) the number of months (not to exceed 12 months, counting any portion of a month as a month)— (i) for which the annuity was payable from the Fund before the effective date of the increase, or (ii) in the case of a widow, widower, former spouse, or insurable interest designee of a deceased annuitant whose annuity has not been so increased, since the annuity was first payable to the deceased annuitant.

(2) Effective from its commencing date, an annuity payable from the Fund to an annuitant’s survivor (except a child entitled under section 8341(e) of this title), which annuity commences the day after the death of the annuitant and after the effective date of the first increase under this section, shall be increased by the total percent increase the annuitant was receiving under this section at death. However, the increase in a survivor annuity authorized by section 8 of the Act of May 29, 1930, as amended to July 6, 1950, shall be computed as if the annuity commencing date had been the effective date of the first increase under this section.

(3) For the purpose of computing the annuity of a child under section 8341(e) of this title that commences after October 31, 1969, the items $900, $1,080, $2,700, and $3,240 appearing in section 8341(e) of this title shall be increased by the total percent increases allowed and in force under this section on or after such day and, in case of a deceased annuitant, the items 60 percent and 75 percent appearing in section 8341(e) of this title shall be increased by the total percent allowed and in force to the annuitant under this section on or after such day.

This section does not authorize an increase in an additional annuity purchased at retirement by voluntary contributions.

The monthly installment of annuity after adjustment under this section shall be rounded to the next lowest dollar. However, the monthly installment shall after adjustment reflect an increase of at least $1.

Effective September 1, 1966, or on the commencing date of annuity, whichever is later, the annuity of each surviving spouse whose entitlement to annuity payable from the Fund resulted from the death of—

(1) an employee or Member before October 11, 1962; or

(2) a retired employee or Member whose retirement was based on a separation from service before October 11, 1962;

An annuity shall not be increased by reason of any adjustment under this section to an amount which exceeds the greater of—

An annuity shall not be increased by reason of any adjustment under this section to an amount which exceeds the greater of—

(A) the maximum pay payable for GS–15 30 days before the effective date of the adjustment under this section; or

(B) the final pay (or average pay, if higher) of the employee or Member with respect to whom the annuity is paid, increased by the overall annual average percentage adjustments (compounded) in rates of pay of the General Schedule under subchapter I of chapter 53 of this title during the period— (i) beginning on the date the annuity commenced (or, in the case of a survivor of the retired employee or Member, the date the employee’s or Member’s annuity commenced), and (ii) ending on the effective date of the adjustment under this section.

(2) For the purposes of paragraph (1) of this subsection, “pay” means the rate of salary or basic pay as payable under any provision of law, including any provision of law limiting the expenditure of appropriated funds.

(Pub. L. 89–554, Sept. 6, 1966, 80 Stat. 576; Pub. L. 90–83, § 1(79), Sept. 11, 1967, 81 Stat. 215; Pub. L. 91–93, title II, § 204, Oct. 20, 1969, 83 Stat. 139; Pub. L. 93–136, § 1, Oct. 24, 1973, 87 Stat. 490; Pub. L. 94–126, § 2(b), Nov. 12, 1975, 89 Stat. 679; Pub. L. 94–183, § 2(35), Dec. 31, 1975, 89 Stat. 1058; Pub. L. 94–440, title XIII, § 1306(a), (c)(1), Oct. 1, 1976, 90 Stat. 1462; Pub. L. 95–454, title IX, § 906(a)(2), (3), Oct. 13, 1978, 92 Stat. 1224; Pub. L. 96–499, title IV, § 401(a), Dec. 5, 1980, 94 Stat. 2605; Pub. L. 97–35, title XVII, § 1702(a), (b), Aug. 13, 1981, 95 Stat. 754; Pub. L. 97–253, title III, §§ 304(a), 309(a), Sept. 8, 1982, 96 Stat. 795, 798; Pub. L. 98–270, title II, § 201(a), Apr. 18, 1984, 98 Stat. 157; Pub. L. 98–369, div. B, title II, § 2201(b), July 18, 1984, 98 Stat. 1058; Pub. L. 99–251, title II, § 204, Feb. 27, 1986, 100 Stat. 25.)