42 CFR § 424.51
Payment to the provider
June 11, 2020
(a) Basic rule. Except as specified in paragraph (b) of this section, Medicare pays the provider for services furnished by a provider.
(b) Exception. Medicare pays the beneficiary for outpatient hospital services if the hospital has collected an amount in excess of the unmet deductible and coinsurance, as specified in §489.30(b)(4) of this chapter.