Treasury Regulations (26 C.F.R.)
26 CFR § 1.617-5 — Effective/applicability date.
Sections 1.617-3 and 1.617-4 apply on and after January 19, 2017. For rules before January 19, 2017, see §§ 1.617-3 and 1.617-4 as contained in 26 CFR part 1 revised as of April 1, 2016.
Source: official text