12 C.F.R. § 615.5451
Book-entry and definitive securities
Subject to subpart C of this part:
(a) Farm Credit banks operating under the same title of the Act may issue consolidated securities in book-entry form.
(b) Farm Credit banks may issue Systemwide securities in book-entry form.
(c) Consolidated and Systemwide securities also may be issued in either registered or bearer definitive form.