(a) In general. Section 860 and §§ 1.860-1 through 1.860-4 apply with respect to determinations after November 6, 1978.

(b) Prior determination of real estate investments trusts. Section 859 (as in effect before the enactment of the Revenue Act of 1978) applies to determinations with respect to real estate investment trusts occurring after October 4, 1976, and before November 7, 1978. In the case of such a determination, the rules in §§ 1.860-1 through 1.860-4 apply, a reference in this chapter 1 to section 860 (or to a particular provision of section 860) shall be considered to be a reference to section 859 (or to the corresponding substantive provision of section 859), as in effect before enactment of the Revenue Act of 1978, and “qualified investment entity” in §§ 1.381(c)25-1(a) and 1.860-1 through 1.860-3 means a real estate investment trust.