The period during which an individual is entitled to benefits under the insurance program established by this part (hereinafter referred to as his “coverage period”) shall begin on whichever of the following is the latest:

(1) July 1, 1966, or (in the case of a disabled individual who has not attained age 65) July 1, 1973; or

in the case of an individual who enrolls pursuant to subsection (d) of section 1395p of this title before the month in which he first satisfies paragraph (1) or (2) of section 1395o of this title, the first day of such month, or

(A) in the case of an individual who enrolls pursuant to subsection (d) of section 1395p of this title before the month in which he first satisfies paragraph (1) or (2) of section 1395o of this title, the first day of such month, or

(B) in the case of an individual who enrolls pursuant to such subsection (d) in the month in which he first satisfies such paragraph, the first day of the month following the month in which he so enrolls, or

(C) in the case of an individual who enrolls pursuant to such subsection (d) in the month following the month in which he first satisfies such paragraph, the first day of the second month following the month in which he so enrolls, or

(D) in the case of an individual who enrolls pursuant to such subsection (d) more than one month following the month in which he satisfies such paragraph, the first day of the third month following the month in which he so enrolls, or

(E) in the case of an individual who enrolls pursuant to subsection (e) of section 1395p of this title, the July 1 following the month in which he so enrolls; or

in the case of an individual who is deemed to have enrolled on or before the last day of the third month of his initial enrollment period, the first day of the month in which he first meets the applicable requirements of section 1395o of this title or July 1, 1973, whichever is later, or

(A) in the case of an individual who is deemed to have enrolled on or before the last day of the third month of his initial enrollment period, the first day of the month in which he first meets the applicable requirements of section 1395o of this title or July 1, 1973, whichever is later, or

(B) in the case of an individual who is deemed to have enrolled on or after the first day of the fourth month of his initial enrollment period, as prescribed under subparagraphs (B), (C), (D), and (E) of paragraph (2) of this subsection.

An individual’s coverage period shall continue until his enrollment has been terminated—

(1) by the filing of notice that the individual no longer wishes to participate in the insurance program established by this part, or

(2) for nonpayment of premiums.

In the case of an individual satisfying paragraph (1) of section 1395o of this title whose entitlement to hospital insurance benefits under part A is based on a disability rather than on his having attained the age of 65, his coverage period (and his enrollment under this part) shall be terminated as of the close of the last month for which he is entitled to hospital insurance benefits.

No payments may be made under this part with respect to the expenses of an individual unless such expenses were incurred by such individual during a period which, with respect to him, is a coverage period.

Notwithstanding subsection (a), in the case of an individual who enrolls during a special enrollment period pursuant to section 1395p(i)(3) or 1395p(i)(4)(B) of this title—

(1) in any month of the special enrollment period in which the individual is at any time enrolled in a plan (specified in subparagraph (A) or (B), as applicable, of section 1395p(i)(3) of this title or specified in section 1395p(i)(4)(A)(i) of this title) or in the first month following such a month, the coverage period shall begin on the first day of the month in which the individual so enrolls (or, at the option of the individual, on the first day of any of the following three months), or

(2) in any other month of the special enrollment period, the coverage period shall begin on the first day of the month following the month in which the individual so enrolls.

Notwithstanding subsection (a), in the case of an individual who enrolls during a special enrollment period pursuant to section 1395p(k) of this title, the coverage period shall begin on the first day of the month following the month in which the individual so enrolls.

(Aug. 14, 1935, ch. 531, title XVIII, § 1838, as added Pub. L. 89–97, title I, § 102(a), July 30, 1965, 79 Stat. 305; amended Pub. L. 90–248, title I, § 145(c), Jan. 2, 1968, 81 Stat. 859; Pub. L. 92–603, title II, §§ 201(c)(3), 206(b), (c), 257(a), Oct. 30, 1972, 86 Stat. 1373, 1378, 1447; Pub. L. 96–499, title IX, §§ 945(c)(1), 947(b), Dec. 5, 1980, 94 Stat. 2642, 2643; Pub. L. 97–35, title XXI, §§ 2106(b)(2), 2151(a)(3), Aug. 13, 1981, 95 Stat. 792, 802; Pub. L. 98–369, div. B, title III, § 2338(c), July 18, 1984, 98 Stat. 1092; Pub. L. 99–272, title IX, § 9201(c)(2), Apr. 7, 1986, 100 Stat. 171; Pub. L. 99–509, title IX, § 9344(b)(1), Oct. 21, 1986, 100 Stat. 2042; Pub. L. 103–432, title I, § 147(f)(1)(B), Oct. 31, 1994, 108 Stat. 4430; Pub. L. 105–33, title IV, § 4581(b)(2), Aug. 5, 1997, 111 Stat. 465; Pub. L. 108–173, title VII, § 736(b)(6), Dec. 8, 2003, 117 Stat. 2356; Pub. L. 109–171, title V, § 5115(a)(2)(B), Feb. 8, 2006, 120 Stat. 46.)