Must a bank file a SAR even if the amount is under 5M? Is the 5M benchmark under the old rules? What if there is no dollar amount?

There are different thresholds for different activities. For instance, if the suspicious activity is connected to an insider (officer, employee, etc.) than there is no dollar threshold. Most SAR's (structuring transactions, check kiting, making false statements, loan fraud, etc.) are reported when the transaction(s) is >$5,000 and you know the suspect. The threshold is raised to $25,000 if you don't know the suspect.

You asked "what if there is no dollar amount?" What type of situation do you have in mind? Maybe we can apply a more specific answer if you give us some details.