42 CFR § 600.520 - General cost-sharing protections.
(a) Cost-sharing protections for lower income enrollees. The State may vary premiums and cost sharing based on household income only in a manner that does not favor enrollees with higher income over enrollees with lower income.
(1) The standards in accordance with 45 CFR 156.420(c) and (e); and
(2) The cost-sharing reduction standards in accordance with 45 CFR 156.420(a)(1) for an enrollee with household income at or below 150 percent of the FPL, and 45 CFR 156.420(a)(2) for an enrollee with household income above 150 percent of the FPL.
(3) The State must establish an effective system to monitor compliance with the cost-sharing reduction standards in paragraph (c) of this section, and the cost-sharing protections to ensure enrollment of Indians in paragraph (b) of this section to ensure that enrollees are not held responsible for such monitoring activity.
(d) Acceptance of certain third party payments. States must ensure that standard health plans must accept premium and cost-sharing payments from the following third party entities on behalf of plan enrollees:
(1) Ryan White HIV/AIDS Programs under title XXVI of the Public Health Service Act;
(3) State and federal government programs.