Entities subject to Federal Trade Commission jurisdiction, such as mortgage brokers and lenders, must maintain "[c]opies of all materially different communications as well as . . . marketing materials regarding any term of any mortgage credit product" for two years from the date the entity last made or disseminated the commercial communications. 12 C.F.R. § 1014.5(a).
Commercial communications include "any written or oral statement, illustration, or depiction . . . that is designed to effect a sale or create interest in purchasing goods or services, whether it appears on or in . . . the internet, cellular network or any other medium. Promotional materials and items and Web pages are included in the term commercial communication." 12 C.F.R. § 1014.2.
Link to the Regulation: https://www.ecfr.gov/cgi-bin/text-idx?SID=dc103ebf9e4d2048a35228719da72320&mc=true&node=pt12.8.1014&rgn=div5