42 CFR §423.642

1. (a)When CMS makes a contract determination under § 423.641, it gives the PDP sponsor written notice.
2. (b)The notice specifies the—
   1. (1)Reasons for the determination; and
   2. (2)The Part D sponsor's right to request a hearing.
3. (c)CMS-initiated terminations—(1) General rule. Except as provided in (c)(2) of this section, CMS mails notice to the Part D plan sponsor 45 calendar days before the anticipated effective date of the termination.
   1. (2)Exception. If a contract is terminated in accordance with § 423.509(b)(2)(i) of this part, CMS notifies the Part D plan sponsor of the date that it will terminate the Part D plan sponsor's contract.
4. (d)When CMS determines that it will not authorize a contract renewal, CMS mails the notice to the Part D sponsor by August 1 of the current contract year.