The regulations in this part are applicable only to U.S. bearer securities[1] presented:
(a) By or through banks for payment at or after their maturity or call date, or in exchange for any securities under any exchange offering,
(b) By banks for conversion to book-entry securities,
(c) By or through banks at any time prior to their maturity or call date for redemption at par and application of the entire proceeds in payment of Federal estate taxes, provided said securities by the terms of their issue are eligible for such redemption, and
(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.