Securities that are not represented by engraved pieces of paper but are maintained in computerized records at the Fed in the names of member banks, which in turn keep records of the securities they own as well as those they are holding for customers. In the case of other securities where a book-entry has developed, engraved securities do exist somewhere in quite a few cases. These securities do not move from holder to holder but are usually kept in a central clearinghouse or by another agent.