42 C.F.R. § 423.420 Solvency standards for non-licensed entities.
Title 42 - Public Health
(a) Establishment and publication. CMS establishes and publishes reasonable financial solvency and capital adequacy standards for entities specified in paragraph (b) of this section. (b) Compliance with standards. A PDP sponsor that is not licensed by a State and for which a waiver application is approved by CMS under §423.410 or §423.415 must maintain reasonable financial solvency and capital adequacy in accordance with the standards established by CMS under paragraph (a) of this section.
Title 42: Public Health
PART 423—VOLUNTARY MEDICARE PRESCRIPTION DRUG BENEFIT
Subpart I—Organization Compliance with State Law and Preemption by Federal Law
§ 423.420 Solvency standards for non-licensed entities.

