45 C.F.R. § 156.460

(a) Reduction of enrollee's share of premium to account for advance payments of the premium tax credit. A QHP issuer that receives notice from the Exchange that an individual enrolled in the issuer's QHP is eligible for an advance payment of the premium tax credit must—

(1) Reduce the portion of the premium charged to or for the individual for the applicable month(s) by the amount of the advance payment of the premium tax credit;

(2) Notify the Exchange of the reduction in the portion of the premium charged to the individual in accordance with § 156.265(g); and

(3) Include with each billing statement, as applicable, to or for the individual the amount of the advance payment of the premium tax credit for the applicable month(s), and the remaining premium owed.

(b) Delays in payment. A QHP issuer may not refuse to commence coverage under a policy or terminate coverage on account of any delay in payment of an advance payment of the premium tax credit on behalf of an enrollee if the QHP issuer has been notified by the Exchange under § 155.340(a) of this subchapter that the QHP issuer will receive such advance payment.

(c) Refunds to enrollees for improper reduction of enrollee's share of premium to account for advance payments of the premium tax credit. If a QHP issuer discovers that it did not reduce the portion of the premium charged to or for an enrollee for the applicable month(s) by the amount of the advance payment of the premium tax credit in accordance with paragraph (a)(1) of this section, the QHP issuer must notify the enrollee of the improper reduction within 45 calendar days of the QHP issuer's discovery of the improper reduction and refund any excess premium paid by or for the enrollee, as follows:

(1) Unless a refund is requested by or for the enrollee, the QHP issuer must, within 45 calendar days of discovery of the error, apply the excess premium paid by or for the enrollee to the enrollee's portion of the premium (or refund the amount directly). If any excess premium remains, the QHP issuer must apply the excess premium to the enrollee's portion of the premium for each subsequent month for the remainder of the period of enrollment or benefit year until the excess is fully applied (or refund the remaining amount directly). If any excess premium remains at the end of the period of enrollment or benefit year, the QHP issuer must refund any excess premium within 45 calendar days of the end of the period of enrollment or benefit year, whichever comes first.

(2) If a refund is requested by or for the enrollee, the refund must be provided within 45 calendar days of the date of the request.