who should sign a signature card for a minor when parents open savings accounts for newborns or kiddos that are not old enough to sign - we have audited signature cards and have found inconsistencies.

we have some where a parent has signed the child's name
we have some that the parent has signed the parent's name on the child's name line

we have some where the child's signature line has not been signed - the parents have only signed their part of the signature card & will later have the card signed when the child is old enough to sign

The answer depends on the laws of your state governing minors. Some states allow minors to enter into a legal agreement such as a deposit contract, if they can sign their name some do not. Most states have some form of the Uniform Transfer to Minors Act where a responsible person is the custodian of the funds on a minor's behalf and the minor wouldn't sign at all.

If you are seeing inconsistencies, it means your new account staff is making it up as they go along which could present financial and legal risks for the bank down the road.

For what is and isn't permissible in your state and to establish specific procedural requirements for your institution, you should ask legal counsel to review state law.

Our policy is to have the parent sign on behalf of the minor, with their parental role noted:

June Cleaver
Mother of Theodore Cleaver

how would these be treated for a FDIC insurance - will it matter if that minor signed or the parents signed on their behalf?

State law may allow a bank to contract with a minor for a deposit account. I am really unsure how someone contracts with a minor if they are unable to sign their name to the contract or are not old enough to understand the basics of what they are signing. I doubt that State law would have any provisions that allows a parent to contract on behalf of the minor in their stead. If the minor is not old enough to actually enter into the contract, they have no business being on the account.

My previous experience has been that if the child can sign their name, they are required to. If they are not able to sign their name (such as an infant), the account must be opened as a custodial account.