(a) Surety bonds required under the provisions of this part may be given only with corporate sureties holding certificates of authority from the Secretary of the Treasury as acceptable sureties on Federal bonds. Each bond and each extension of coverage of bond shall at the time of filing be accompanied by a power of attorney authorizing the agent or officer who executed the bond to so act on behalf of the surety. The appropriate TTB officer who is authorized to approve the bond may, whenever he deems it necessary, require additional evidence of the authority of the agent or officer to execute the bond or extension of coverage of bond. The power of attorney shall be prepared on a form provided by the surety company and executed under the corporate seal of the company. If the power of attorney submitted is other than a manually signed document it shall be accompanied by a certificate of its validity. Limitations concerning corporate sureties are prescribed by the Secretary in Treasury Department Circular No. 570, as revised. The surety shall have no interest whatever in the business covered by the bond.

(b) Treasury Department Circular No. 570 (Companies Holding Certificates of Authority as Acceptable Sureties on Federal Bonds and as Acceptable Reinsuring Companies) is published in the Federal Register annually as of the first workday in July. As they occur, interim revisions of the circular are published in the Federal Register. Copies may be obtained from the Audit Staff, Bureau of Government Financial Operations, Department of the Treasury, Washington, DC 20226.