An institutional investor is an entity that pools money to purchase securities, real property, and other investment assets or originate loans. Institutional investors include commercial banks, central banks, credit unions, government-linked companies, insurers, pension funds, sovereign wealth funds, charities, hedge funds, real estate investment trusts, investment advisors, endowments, and mutual funds. Operating companies which invest excess capital in these types of assets may also be included in the term. Activist institutional investors may also influence corporate governance by exercising voting rights in their investments. In 2019, the world's top 500 asset managers collectively managed $104.4 trillion in Assets under Management (AuM).

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 equities and fixed income instruments. In some jurisdictions it includes some instruments that are close to equities and fixed income, e.g., equity warrants.