Section 1.851-1 - Definition of regulated investment company(a)In general. The term "regulated investment company" is defined to mean any domestic corporation (other than a personal holding company as defined in section 542) which meets(1) the requirements of section 851(a) and paragraph (b) of this section, and(2) the limitations of section 851(b) and § 1.851-2 . As to the definition of the term "corporation", see section 7701(a)(3).(b)Requirement. To qualify as a regulated investment company, a corporation must be: (1) Registered at all times during the taxable year, under the Investment Company Act of 1940, as amended (15 U.S.C. 80a - 1 to 80b - 2 ), either as a management company or a unit investment trust, or(2) A common trust fund or similar fund excluded by section 3(c)(3) of the Investment Company Act of 1940 (15 U.S.C. 80a - 3(c) ) from the definition of "investment company" and not included in the definition of "common trust fund" by section 584(a).