If your examiner cited this issue, you might check your loan policy. Most loan policies address overdraft checking with a statement as to when the account will be charged off and examiners then review the accounts to see if you are following your own policy.
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This is probably a state law. For example, in the Utah State Code 7-3-26 states "An overdraft of more than 90 days' standing may not be allowed as an asset of a bank, unless amply secured and in the process of collection."