You can use an abbreviation on statements if you include that same abbreviation in your disclosures when you explain what it means. While I think we all agree that the abbreviation ought to be fairly self-explanatory, you could theoretically list an "ZYX Fee" and explain in your disclosures that it's a fee for returning unpaid items that would overdraw or further overdraw the customer's account.
John S. Burnett
Fighting for Compliance since 1976
Bankers' Threads User #8