12 CFR §7.1001

Pursuant to 12 U.S.C. 92, a national bank may act as an agent for any fire, life, or other insurance company in any place the population of which does not exceed 5,000 inhabitants. This section is applicable to any office of a national bank when the office is located in a community having a population of less than 5,000, even though the principal office of such bank is located in a community whose population exceeds 5,000.