If you have a customer who's business was dissolved years ago, and you receive an IRS summons for them, would you file a SAR on any activity occurring in the account? Further review shows that they have an outstanding state tax warrant.

Account activity in this case is minimal and related to business operations/expenses. No cash activity. Is a SAR filing necessary?

An IRS summons should spur any bank to perform enhanced due diligence on the customer. If you find suspicious activity, you file a SAR. If you don't, you write a memo to file explaining that you looked, but you didn't find anything.

Since you refer to this person as a "customer," I assume you have an account in the name of the now defunct entity. When a bank has a contract (loan or a deposit) with a legal entity that no longer exists, it should begin the process of either aggressively requiring the entity to be reinstated or terminate the relationship.

Thank you for your input!