Book entry in the context of "Broker"

A security is a tradable financial asset. The term commonly refers to any form of financial instrument, but its legal definition varies by jurisdiction. In some countries and languages people commonly use the term "security" to refer to any form of financial instrument, even though the underlying legal and regulatory regime may not have such a broad definition. In some jurisdictions the term specifically excludes financial instruments other than equity and fixed income instruments. In some jurisdictions it includes some instruments that are close to equities and fixed income, e.g., equity warrants.

Securities may be represented by a certificate or, more typically, they may be "non-certificated", that is in electronic (dematerialized) or "book entry only" form. Certificates may be bearer, meaning they entitle the holder to rights under the security merely by holding the security, or registered, meaning they entitle the holder to rights only if they appear on a security register maintained by the issuer or an intermediary. They include shares of corporate capital stock or mutual funds, bonds issued by corporations or governmental agencies, stock options or other options, limited partnership units, and various other formal investment instruments that are negotiable and fungible.

A central securities depository (CSD) is a specialized financial market infrastructure organization holding securities such as shares or bonds, either in certificated or uncertificated (dematerialized) form, allowing ownership to be easily transferred through a book entry rather than by a transfer of physical certificates. This allows brokers and financial companies to hold their securities at one location where they can be available for clearing and settlement. In recent decades this has usually been done electronically, making it much faster and easier than was traditionally the case where physical certificates had to be exchanged after a trade had been completed.

In some cases these organizations also carry out centralized comparison and transaction processing such as clearing and settlement of securities transfers, securities pledges, and securities freezes.

TreasuryDirect is a website run by the Bureau of the Fiscal Service under the United States Department of the Treasury that allows US individual investors to purchase treasury securities, such as savings bonds, directly from the US government. It enables people to manage their investments online, including connecting their TreasuryDirect account to a bank account for deposits and withdrawals.

TreasuryDirect started in 1986 as a book entry system with business conducted over postal mail, as an alternative to purchasing securities as engraved paper certificates. The current online system launched in 2002. A replacement system known as TRIM has been in progress since 2013, but after a decade of development, the project is at risk with higher than planned costs.

The indirect holding system (also multi-tiered holding system) is a system of securities clearance, settlement and ownership system where ownership information is held electronically as a book entry. It consists of one or more tiers of intermediaries between issuer and investor. It is an evolution from the "direct holding system" in which owners of securities had a direct relationship with the issuer.

The system is made up of various tiers, often with an increasing number of entries involved in each of the tiers. The top tier comprises "national" and "international central securities depositories" (CSDs), where large pools of securities of different issuers are immobilized or otherwise concentrated.