---
kind: "section"
citation: "42 C.F.R. § 424.522"
title: "42"
number: "424.522"
heading: "Additional effective dates."
url: "https://uscodex.org/cfr/42/424.522"
---

# §424.522. Additional effective dates.

- (a) **Reassignments.**
  - (1) The effective date of a reassignment of benefits under [§ 424.80](/cfr/42/424.80.md) is the later of the dates identified in § [424.520(d)(1)(i)](/cfr/42/424.520.md?p=d-1-i) and [(ii)](/cfr/42/424.520.md?p=d-1-ii).
  - (2) Retrospective billing in accordance with a reassignment of benefits and as described in [§ 424.521(a)(1)](/cfr/42/424.521.md?p=a-1) is permissible if the circumstances in [§ 424.521(a)(1)](/cfr/42/424.521.md?p=a-1) are applicable.
- (b) **Form CMS-855O enrollment.** The effective date of a Form CMS-855O enrollment is the date on which the Medicare contractor received the Form CMS-855O application if all other requirements are met.

## Notes

### Amendments

[86 FR 62419, Nov. 9, 2021, as amended at 90 FR 55617, Dec. 2, 2025]

### Source

Source: 71 FR 20776, Apr. 21, 2006, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 1302 and 1395hh.

### Source

Source: 53 FR 6634, Mar. 2, 1988, unless otherwise noted.

### Amendments

[86 FR 62419, Nov. 9, 2021, as amended at 90 FR 55617, Dec. 2, 2025]