§ 423.780 Premium subsidy.
(a) Full subsidy eligible individuals. Full subsidy eligible individuals are entitled to a premium subsidy equal to 100 percent of the premium subsidy amount.
(b) Premium subsidy amount. (1) The premium subsidy amount is equal to the lesser of—
(i) Under the Part D plan selected by the beneficiary, the portion of the monthly beneficiary premium attributable to basic coverage (for enrollees in PDPs) or the portion of the MA monthly prescription drug beneficiary premium attributable to basic prescription drug coverage (for enrollees in MA–PD plans); or
(ii) The greater of the low-income benchmark premium amount (determined under paragraph (b)(2) of this section) for the PDP region in which the subsidy eligible individual resides or the lowest monthly beneficiary premium for a PDP that offers basic prescription drug coverage in the PDP region.
(2) Calculation of the low-income benchmark premium amount. (i) The low-income benchmark premium amount for a PDP region is a weighted average of the premium amounts described in paragraph (b)(2)(ii) of this section, with the weight for each PDP and MA–PD plan equal to a percentage, the numerator being equal to the number of Part D low-income subsidy eligible individuals enrolled in the plan in the reference month (as defined in § 422.258(c)(1) of this chapter) and the denominator equal to the total number of Part D low-income subsidy eligible individuals enrolled in all PDP and MA–PD plans (but not including PACE, private fee-for-service plans or 1876 cost plans) in a PDP region in the reference month.