What is the retention period for information supporting each designation of an exempt person?

There are two subsections of 31 CFR Part 103 that come to bear on this question.

Subsection 103.22(d)(6)(x) reads:

The records maintained by a bank to document its compliance with and administration of the rules of this paragraph (d) shall be maintained in accordance with the provisions of Sec. 103.38.

Subsection 103.38(d) reads, in pertinent part:

All records that are required to be retained by this part shall be retained for a period of five years. ...

Summing up: Five years.

John,
Thanks for coming to my rescue! Much appreciated.