Legal Definitions - irregular indorsement

An irregular indorsement is when a person signs the back of a negotiable instrument, like a check, but they are not part of the chain of ownership. This means they are not the original owner or a subsequent owner who received the instrument through a proper transfer. An irregular indorser is usually treated as an accommodation party, which means they are not liable for the payment of the instrument unless certain conditions are met.

For example, if John receives a check made out to him and he signs the back of the check to transfer it to Jane, who then signs it to transfer it to Tom, but then Tom signs it and gives it to Sarah, who is not part of the chain of ownership, Sarah has made an irregular indorsement. She is not liable for the payment of the check unless she made certain promises or guarantees when she signed it.