When both the bank and the customer failed to use ordinary care to prevent alteration or forgery of checks then a comparative negligence is used to determine liability for damages.

Comparative Negligence

A legal doctrine that distributes the responsibility and damages among the parties involved in an accident based on their respective degrees of fault.

Ordinary Care

The standard of care that a reasonably prudent person would use in a similar situation to avoid harm to others.

Alteration

The act of modifying or changing something, often referring to documents, clothing, or physical structures.