3. Limitations on Effectiveness of Notification. Subsection (b) [Maine cite subsection (2)] contains some special rules concerning the effectiveness of a notification under subsection (a) [Maine cite subsection (1)].

Subsection (b)(1) [Maine cite subsection (2), paragraph (a)] tracks former Section 9-318(3) by making ineffective a notification that does not reasonably identify the rights assigned. A reasonable identification need not identify the right to payment with specificity, but what is reasonable also is not left to the arbitrary decision of the account debtor. If an account debtor has doubt as to the adequacy of a notification, it may not be safe in disregarding the notification unless it notifies the assignee with reasonable promptness as to the respects in which the account debtor considers the notification defective.

Subsection (b)(2) [Maine cite subsection (2), paragraph (b)], which is new, applies only to sales of payment intangibles. It makes a notification ineffective to the extent that other law gives effect to an agreement between an account debtor and a seller of a payment intangible that limits the account debtor's duty to pay a person other than the seller. Payment intangibles are substantially less fungible than accounts and chattel paper. In some (e.g., commercial bank loans), account debtors customarily and legitimately expect that they will not be required to pay any person other than the financial institution that has advanced funds.

It has become common in financing transactions to assign interests in a single obligation to more than one assignee. Requiring an account debtor that owes a single obligation to make multiple payments to multiple assignees would be unnecessarily burdensome. Thus, under subsection (b)(3) [Maine cite subsection (2), paragraph (c)], an account debtor that is notified to pay an assignee less than the full amount of any installment or other periodic payment has the option to treat the notification as ineffective, ignore the notice, and discharge the assigned obligation by paying the assignor. Some account debtors may not realize that the law affords them the right to ignore certain notices of assignment with impunity. By making the notification ineffective at the account debtor's option, subsection (b)(3) [Maine cite subsection (2), paragraph (c)] permits an account debtor to pay the assignee in accordance with the notice and thereby to satisfy its obligation pro tanto. Under subsection (g) [Maine cite subsection (7)], the rights and duties created by subsection (b)(3) [Maine cite subsection (2), paragraph (c)] cannot be waived or varied.

4. Proof of Assignment. Subsection (c) [Maine cite subsection (3)] links payment with discharge, as in subsection (a) [Maine cite subsection (1)]. It follows former Section 9- 318(3) in referring to the right of the account debtor to pay the assignor if the requested proof of assignment is not seasonably forthcoming. Even if the proof is not forthcoming, the notification of assignment would remain effective, so that, in the absence of reasonable proof of the assignment, the account debtor could discharge the obligation by paying either the assignee or the assignor. Of course, if the assignee did not in fact receive an assignment, the account debtor cannot discharge its obligation by paying a putative assignee who is a stranger. The observations in Comment 3 concerning the reasonableness of an identification of a right to payment also apply here. An account debtor that questions the adequacy of proof submitted by an assignor would be well advised to promptly inform the assignor of the defects.

An account debtor may face another problem if its obligation becomes due while the account debtor is awaiting reasonable proof of the assignment that it has requested from the assignee. This section does not excuse the account debtor from timely compliance with its obligations. Consequently, an account debtor that has received a notification of assignment and who has requested reasonable proof of the assignment may discharge its obligation by paying the assignor at the time (or even earlier if reasonably necessary to avoid risk of default) when a payment is due, even if the account debtor has not yet received a response to its request for proof. On the other hand, after requesting reasonable proof of the assignment, an account debtor may not discharge its obligation by paying the assignor substantially in advance of the time that the payment is due unless the assignee has failed to provide the proof seasonably.

5. Contractual Restrictions on Assignment. Former Section 9- 318(4) rendered ineffective an agreement between an account debtor and an assignor which prohibited assignment of an account (whether outright or to secure an obligation) or prohibited a security assignment of a general intangible for the payment of money due or to become due. Subsection (d) [Maine cite subsection (4)] essentially follows former Section 9-318(4), but expands the rule of free assignability to chattel paper (subject to Sections 2-1303 and 9-407 [Maine cite section 9-1407]) and promissory notes and explicitly overrides both restrictions and prohibitions of assignment. The policies underlying the