N.D. Cent. Code § 41-03-43

(4) Subsection (b) differs from former Section 3-406 in that it adopts a concept of comparative negligence. If the person precluded under subsection (a) proves that the person asserting the preclusion failed to exercise ordinary care and that failure substantially contributed to the loss, the loss may be allocated between the two parties on a comparative negligence basis. In the case of a forged indorsement the litigation is usually between the payee of the check and the depositary bank that took the check for collection. An example is a case like Case # 1 of Comment 3 to Section 3-405. If the trier of fact finds that Employer failed to exercise ordinary care in safeguarding the check and that the failure substantially contributed to the making of the forged indorsement, subsection (a) of Section 3-406 applies. If Employer brings an action for conversion against the depositary bank that took the checks from the forger, the depositary bank could assert the preclusion under subsection (a). But suppose the forger opened an account in the depositary bank in a name identical to that of Employer, the payee of the check, and then deposited the check in the account. Subsection (b) may apply. There may be an issue whether the depositary bank should have been alerted to possible fraud when a new account was opened for a corporation shortly before a very large check payable to a payee with the same name is deposited. Circumstances surrounding the opening of the account may have suggested that the corporation to which the check was payable may not be the same as the corporation for which the account was opened. If the trier of fact finds that collecting the check under these circumstances was a failure to exercise ordinary care, it could allocate the loss between the depositary bank and Employer, the payee.