20 CFR § 404.145
When you acquire a quarter of coverage
February 18, 2021
If we credit you with a quarter of coverage (QC) for a calendar quarter under paragraph (b), (c), or (d) of §404.141 for calendar years before 1978 or assign it to a specific calendar quarter under paragraph (b) of §404.143 for calendar years after 1977, you acquire the QC as of the first day of the calendar quarter.