Central Securities Depository (CSD) are Entities holding securities either in certificated or uncertificated (dematerialized) form, to enable book-entry transfer of securities. In some cases these organizations also carry out centralized comparison, clearing and settlement of securities. It is an institution for holding securities, which enables securities transactions to be processed by means of book entries. Physical securities may be immobilised by the depository or securities may be dematerialised (so that they exist only as electronic records).

International central securities depository (ICSD) is a central securities depository that settles trades in international securities and in various domestic securities, usually through direct or indirect (through local agents) links to local CSDs. ClearStream International (earlier Cedel), EuroClear and SegaInterSettle are considered ICSDs. Various

Functions of the Depository are:

Safekeeping: Securities may be in dematerialized form (book-entry only) or in physical form immobilized within the CSD.

Deposit and Withdrawal: Supporting deposits and withdrawals involves the relationship between the transfer agent and/or issuers and the CSD. It also covers the CSD's role within the underwriting process or listing of new issues in a market.

Dividend, interest and principal processing, as well as corporate actions including proxy voting: Paying and transfer agents, as well as issuers are involved in these processes, depending on the level of services provided by the CSD and its relationship with these entities.

Other services: CSDs offer additional services aside from those considered core services. These services include Securities Lending and Borrowing, Matching, Repo Settlement etc.

However, there are risks and responsibilities regarding these services that must be taken into consideration in analyzing and evaluating each market on a case-by-case basis.