My bank provides "Confirmation of Certificate (CD) Renewal" notices to customers. These notices are provided subsequent to the CD renewal date. The problem is that only the interest rate is detailed on these notices...no APY. Management contends that since the notices aren't required anyway, the APY does not need to be listed. Intuitively, this seems wrong to me; however, I was unable to find anything in the Reg to support my position. Could these notices be considered an advertisement?

They don't meet the definition of advertisement, since they are not designed to attract or retain deposit dollars. They are simply informational. It's a service to your customer to give them a piece of information they might not otherwise have obtained. If you find that customers routinely call to get the rate and APY on or after renewal date, the notice is superfluous and you could consider killing it off.