Code of Federal Regulations Title 31. Money and Finance–Treasury § 31.356.4 What are the book-entry systems in which auctioned Treasury securities may be issued or maintained?

(a) The commercial book-entry system. When depository institutions or dealers submit bids for Treasury securities in an auction, securities awarded as a result of those bids are generally held in the commercial book-entry system. Specifically, we maintain book-entry accounts in the National Book–Entry System® (“NBES”) for Federal Reserve Banks, depository institutions, and other authorized entities, such as government and international agencies and foreign central banks. In their accounts, depository institutions maintain securities held for their own account and for the accounts of others. The accounts held for others include those of other depository institutions and dealers, which may, in turn, maintain accounts for others.

(b) TreasuryDirect. In this system, account holders maintain accounts in a book-entry, online system directly on the records of the Bureau of the Fiscal Service, Department of the Treasury. Bids for securities to be held in TreasuryDirect are submitted through the Internet.

(c) Legacy Treasury Direct. In this system, we maintain the book-entry securities of account holders directly on the records of the Bureau of the Fiscal Service, Department of the Treasury. Bids for securities to be held in Legacy Treasury Direct are submitted directly to us. From time to time, Treasury may announce that certain securities to be offered will not be eligible for purchase or holding in Legacy Treasury Direct.