Rule 31a-2 under the Investment Company Act of 1940 ("Act") (17 CFR 270.31a-2) specifies the time periods that entities must retain certain books and records, including those required to be maintained under rule 31a-1 under the Act.
The latest form for Rule 31a-2: Records to be preserved by registered investment companies, certain majority-owned subsidiaries thereof, and other persons having transactions with registered investment companies. expires 2023-01-31 and can be found here.