17 C.F.R. § 270.30a-1
Every management investment company must file an annual report on Form N-CEN (§ 274.101 of this chapter) at least every twelve months and not more than seventy-five calendar days after the close of each fiscal year. Every unit investment trust must file an annual report on Form N-CEN (§ 274.101 of this chapter) at least every twelve months and not more than seventy-five calendar days after the close of each calendar year. A registered investment company that has filed a registration statement with the Commission registering its securities for the first time under the Securities Act of 1933 is relieved of this reporting obligation with respect to any reporting period or portion thereof prior to the date on which that registration statement becomes effective or is withdrawn.
17 C.F.R. §270.30a-1