45 CFR § 155.240 - Payment of premiums.
(b) Payment by tribes, tribal organizations, and urban Indian organizations. The Exchange may permit Indian tribes, tribal organizations and urban Indian organizations to pay aggregated QHP premiums on behalf of qualified individuals, including aggregated payment, subject to terms and conditions determined by the Exchange.
(c) Payment facilitation. The Exchange may establish a process to facilitate through electronic means the collection and payment of premiums to QHP issuers.
(d) Required standards. In conducting an electronic transaction with a QHP issuer that involves the payment of premiums or an electronic funds transfer, the Exchange must comply with the privacy and security standards adopted in accordance with § 155.260 and use the standards and operating rules referenced in § 155.270.
(e) Premium calculation. The Exchange may establish one or more standard processes for premium calculation.
(i) The premium for one month of coverage divided by the number of days in the month; and
(ii) The number of days for which coverage is being provided in the month described in paragraph (e)(1)(i) of this section.