If we cannot promptly collect all of the remittance for a security, we may in our discretion cancel the security unless it has been legally transferred for value to a third person who had no knowledge of the improper debit entry at the time of the transfer.

We reserve the right, in our discretion, to waive any provision of these regulations in any case or class of cases. We may do so if such action is not inconsistent with law and will not subject the United States to substantial expense or liability.

Any aspect of this part may be changed at any time and without notice. You assume the risk that a change may terminate a provision that was to your advantage. Nothing in this part creates vested rights in your favor.