; reinsurance (a) Premium amounts The Secretary shall establish premiums for the health plan that cover the full actuarial cost of offering such plan, including the administrative costs of offering such plan. Such premiums shall vary geographically and between the small group market and the individual market in accordance with differences in the cost of providing such coverage. If, for any plan year, the amount collected in premiums exceeds the amount required for health care benefits and administrative costs in that plan year, such excess amounts shall remain available to the Secretary to administer the health plan and finance beneficiary costs in subsequent years. (b) Risk pool All enrollees in the health plan within a State shall be members of a single risk pool, except that the Secretary may establish separate risk pools for the individual market and small group market if the State has not exercised its authority under section 1312(c)(3) of the Patient Protection and Affordable Care Act ( 42 U.S.C. 18032(c)(3) ). (c) Reinsurance Notwithstanding subsection (b), the Secretary may establish a mechanism to pool the costs of the highest-cost patients on a nationwide basis to the extent such costs are not already pooled pursuant to section 1343 of the Patient Protection and Affordable Care Act ( 42 U.S.C. 18063 ). 2207. Reimbursement rates (a) Medicare rates (1) In general Except as provided in paragraph (2) and subsections (b) and (c) and subject to subsection (d), the Secretary shall reimburse health care providers furnishing items and services under the health plan at rates determined for equivalent items and services under the original Medicare fee-for-service program under parts A and B of title XVIII. (2) Authority to increase payments rates in rural areas If the Secretary determines appropriate, the Secretary may increase the reimbursements rates described in paragraph (1) by up to 25 percent for items and services furnished in rural areas (as defined in section 1886(d)(2)(D)). (b) Prescription drugs Subject