The whole concept of "availability" doesn't apply to CD deposits in the first place, and even if Reg CC DID apply, the credit to the CD isn't an ACH entry anyhow. It's an internal credit to the CD account, offset by the ACH DEBIT sent to the customer's other bank to pull the funds from there. If that ACH debit gets returned to you for any reason (insufficient funds, their customer stopped payment, the transfer was fraudulent and not authorized by the owner of the account debited, etc.), your bank will be charged for the returned debit and you won't have any choice but to remove the funds from the CD account (or extract it from your customer in some other way, I suppose). You can't refuse a returned ACH debit if it's timely, and some ACH debits can be returned under limited circumstances up to 60 days after their Settlement Dates.
What sort of "unauthorized returns" does management think could occur? Doesn't management understand that a CD account comes with bank control over the funds, if you want it. You can include language in the deposit contract disallowing any early withdrawals, for example. But even that won't protect the bank if the check or ACH debit used to fund the CD bounces.
John S. Burnett
Fighting for Compliance since 1976
Bankers' Threads User #8