We have a high-risk customer that will not stop conducting suspicious activities. They are an MSB who commingles so much that you cant tell what they are exactly doing, but they seem to be bringing in just about as much cash as they take out (about $2 million a month), other MSBs in this area have no where near that volume, they are always structuring, and the amount of service income we receive from them is nothing compared to the cost of my time reviewing their accounts.

Since we absolutely cannot indicate that we've filed a SAR on this customer, how in the world do we agout about notifying them that we wish to end our relationships with them?

Follow the KISS method. Make your notice short and business-like. You have no obligation to tell the customer why you're asking them to take a hike. Simply state that the bank has made a business decision not to continue its deposit relationship with the customer, provide the date by which you intend to close the account, along with instructions on when to stop making deposits, writing checks, etc.

If your signature card agreement indicates you can close an account at anytime, you could say, “Per our deposit account agreement, we have decided to close your accounts.” To protect ourselves from liability, we don't disclose any specific reason.

We just tell them that we feel we can no longer meet their banking needs. If they question it further, I would tell them that part of the reason is that the amount of cash they put through the bank is burdensome to have on hand and to ship out.

Thanks for the input guys!