We have recently started with a new document vendor. Their certificates of deposit require signatures of all account owners when there are more than one. In the past, we only required the signature of one account owner when there were more than one. The new vendor is re-affirming to us that all account owners are required to sign in order to be in compliance. I am unsure of what regulation they would be referring to be in compliance with. I assume they are referring to something in a legal/contractual context. Any help you could provide would be appreciated.

Our CD terms & conditions state that "Only those of you who sign the permanent signature card may withdraw funds from this account." We also require all owners sign the CD agreeing to the terms. If all owners do not sign, then those who did not sign have no rights to withdraw the funds.

You may want to read your account terms & conditions and see what it states.

How would your new document vendor know if you received all the signatures? To me this is a contract law issue not a regulation issue.

Not having all signatures on a joint account will effect your FDIC insurance.

This is a meaningless expression until it's accompanied with a properly cited state or federal law, regulation, or other formal rule. If a vendor is making statements like this, demand a citation every time.

That is true for most joint accounts, but there is a limited exception for certificates of deposit, deposits evidenced by a negotiable instrument, or any account maintained by an agent, nominee, guardian, custodian or conservator on behalf of two or more persons.

See 12 CFR 330.9(c)(2).