(a)General. A savings bond may not be hypothecated, pledged, or used as security for the performance of an obligation, except as provided in paragraph (b) of this section.(b)Pledge under Treasury Circular No. 154. A bond may be pledged by the registered owner in lieu of surety under the provisions of Department of the Treasury Circular No. 154, current revision ( 31 CFR part 225 ), if the bond approving officer is the Secretary of the Treasury. In this case, an irrevocable power of attorney shall be executed authorizing the Secretary of the Treasury to request payment.