31 C.F.R. § 328.1
The regulations in this part are applicable only to U.S. bearer securities 1 presented:
(d) By Service Center Directors and District Directors, Internal Revenue Service, for redemption, with the proceeds to be applied in payment of taxes (other than securities presented under paragraph (c) of this section).
These regulations do not apply to bearer securities presented for any other transactions, or to registered securities assigned in blank, or to bearer, or so assigned as to become, in effect, payable to bearer.
1 Certain agencies of the United States and certain Government and Government-sponsored corporations also authorize the restrictive endorsement of bearer securities.