Here's the situation
Husband withdrawals a substantial amount of money from a joint account. Creates an official check payable to himself. Joint owner wife would like to know where he cashed the check. Can we provide that information to her now that the money is out of the account and was made into a single owned cashiers check?

I would not without a subpoena. The bank does not need to voluntarily place themselves in the middle of a domestic dispute.

Nope. Absolutely wouldn't give out this information without a subpoena as Randy wisely notes. A joint account is just that, joint. Either husband or wife can take action. Any disputes are between them.

No, regardless of whether the parties are married. No, no if the parties are married.

Thank you all. We are definitely not getting in the middle of this one. I appreciate your feedback.