17 CFR § 162.8
Acceptable delivery methods of opt-out notices
April 15, 2021
(a) In general. The opt-out notice must be provided so that each consumer can reasonably be expected to receive actual notice.
(b) Electronic notices. For opt-out notices provided electronically, the notice may be provided in compliance with either the electronic disclosure provisions in §1.4 of this title or the provisions in section 101 of the Electronic Signatures in Global and National Commerce Act, 15 U.S.C. 7001 et seq.