Focus on Rock Chucker's advice and do what is necessary to preserve your career. (Your bank may search for a scapegoat someday. I promise you that your CEO will suggest you are the better choice.)
If your policy provides that repetitive SAR filings be escalated for management consideration, then leave a paper or electronic trail that you attempted to do so even though it' apparent that your CEO is already aware of the facts. Without knowing the exact wording of your policy, I suggest you tell the CEO in writing that this is an appropriate circumstance for escalation, very clearly offer your recommendation that the relationship be discontinued (including closure of the IOLTA account) due the potential loss and risk of public embarrassment, and ask who else he or she would like to involve in the decision.
On verbal discussions: Do not rely on them regardless of the fact that you might write a thrilling memo to file regarding their content. The other party will simply say he or she has no recollection of such a conversation. Had it actually happened, they would certainly have done something about it.
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In this world you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant.