This is not something that is disclosed when the account is opened.
So how do you satisfy the requirement of 1030.4(a)(4)?
(4) Fees. The amount of any fee that may be imposed in connection with the account (or an explanation of how the fee will be determined) and
the conditions under which the fee may be imposed.Even if you make the argument that your disclosures say you charge a fee regardless of amount and then as a courtesy impose a de minimus, changing how fees are charged (particularly for customers who have figured out what the de minimus is) increases UDAP risk.
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