26 C.F.R. § 1.1368-4
Except for §§ 1.1368-1(e)(2) , 1.1368-2(a)(5) , and 1.1368-3 Example 2, Example 4, and Example 5,§§ 1.1368-1 , 1.1368-2 , and 1.1368-3 apply to taxable years of the corporation beginning on or after January 1, 1994. Section 1.1368-1(e)(2) , § 1.1368-2(a)(5) , and § 1.1368-3 Example 2, Example 4, and Example 5 apply only to taxable years of the corporation beginning on or after August 18, 1998. For taxable years beginning before January 1, 1994, and taxable years beginning on or after January 1, 1997, and before August 18, 1998, the treatment of distributions by an S corporation to its shareholders must be determined in a reasonable manner, taking into account the statute and legislative history. Except with regard to the deemed dividend rule under § 1.1368-1(f)(3) , § 1.1368-1(e)(2) , § 1.1368-2(a)(5) , and § 1.1368-3 Example 2, Example 4, and Example 5, return positions consistent with §§ 1.1368-1 , 1.1368-2 , and 1.1368-3 are reasonable for taxable years beginning before January 1, 1994. Return positions consistent with §§ 1.1368-1(e)(2) , 1.1368-2(a)(5) , and 1.1368-3 Example 2, Example 4, and Example 5 are reasonable for taxable years beginning on or after January 1, 1997, and before August 18, 1998.
26 C.F.R. §1.1368-4