Can a bank deposit a check that was payable to my business, but endorsed by a third party and deposited into his own account?
Yes, but it would be an error. Your business hasn't yet been paid, it didn't receive the funds, so you can go back to the issuer of the check and make a claim for non-payment, indicating that the check was stolen and deposited by a third party. Ask the check issuer for a copy of the check, and provide the issuer with an affidavit that your business didn't endorse or receive any benefit from the check. Then ask for a replacement check.
The check issuer then enters a claim against its bank, and each party in turn makes a claim on others who handled the check until a claim is made with the bank that accepted the check for deposit. That's how the issuer gets its money back, and you get paid.
BankingQuestions.com is a free service made possible by the generous support of our advertisers. Advertisers are not responsible for site content. Please help us keep BankingQuestions.com FREE by supporting our advertisers. When you see an ad for a product or service you may have an interest in, click through to learn more.