Sections 31.3406-0 through 31.3406(i)-1 (except §§ 31.3406(d)-5 and 31.3406(g)-1(c) and except for international transactions) are effective after December 31, 1996, and, optionally, for reportable payments made and transactions occurring on or after December 21, 1995. For the effective date of § 31.3406(d)-5, see § 31.3406(d)-5(i). Section 31.3406(g)-1(c) is effective before January 1, 1997. See §§ 35a.9999-0T through 35a.9999-5 of this chapter for rules that apply to international transactions after December 31, 1996.