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What Is a Security?

Learn all about what a security is and how it can impact your financial outlook. Understanding securities and how they function is an important part of becoming financially literate.
Person holding a phone with a price graph for a stock or financial security with text overlay that reads "What Is a Security?"

Financial securities have value and can be bought, sold, and traded. 

What Is a Security?

At a basic level, a security is a financial asset or instrument that has value and can be bought, sold, or traded. Some of the most common examples of securities include stocks, bonds, options, mutual fund shares, and ETF shares. Securities have certain tax implications in the United States and are under tight government regulation.

Characteristics of Securities

  • Securities are fungible. In other words, they are assets that can be exchanged quickly and easily for others of the same type. Just like any one quarter can be replaced by any other, any share of a company’s stock can be replaced by any other share of the same company’s stock. While both quarters and a company’s shares can change in value over time, at any one moment in time, all quarters are worth the same amount, and all shares of a specific company’s stock are worth the same amount.
  • In the United States, the exchange of securities is regulated by the SEC (Securities and Exchange Commission), a regulatory agency of the U.S. Government.
  • The legal definition of a financial security varies between countries and jurisdictions.
  • Securities are usually divided into four general categories—debt, equity, hybrid, and derivative.

The 4 Types of Securities

Financial securities are divided into one of four general categories—debt securities, equity securities, hybrid securities (which have characteristics of both debt and equity securities), and derivative securities.

Debt Securities

Debt securities—like corporate bonds, government bonds, and certificates of deposit—are essentially loans. They act like IOUs from a government or corporation to the debt security holder. Owners of debt securities lend a certain amount of money (the principal) to another party. That party is then obligated to pay pre-determined interest payments to the owner at regular intervals per the terms specified in their agreement until the instrument matures, at which time the debtor must pay back the security owner in the amount of the principal.

The purpose of a debt security (like a bond) is twofold. On one hand, it allows a corporation, government, or other entity (the borrower) the temporary use of the security owner’s capital. On the other hand, it allows the security owner to receive regular interest payments for a period of time in exchange for the temporary use of their money before having it returned to them in full at a certain agreed-upon date.

Equity Securities

Equity securities indicate partial ownership of an entity—often a business. The most common example of an equity security is a share of a company’s stock. Shares of mutual funds are also considered equity securities, as are shares of certain ETFs (those that do not include debt securities like bonds).

While individuals purchase debt securities in order to receive periodic payments in exchange for the temporary use of their money, individuals usually purchase equity securities as investments for the purpose of realizing capital gains over time. An equity security is an asset, so if its value increases, the party that holds it can sell it for a profit.

While most equity securities usually do not entitle their holders to periodic payments, some do, and these payments are called dividends. Companies that pay dividends use a small percentage of their profits to pay shareholders a certain amount of money per share—usually once per quarter or once per year. Because holders of equity securities are partial owners of an entity, they are also often entitled to certain voting rights when it comes to some of that entity’s business decisions.

Generally, equity securities offer higher potential returns than debt securities because a company or entity’s value is technically limitless, whereas a bond’s value, interest payments, and maturity are fixed and pre-determined. Equity securities also come with greater risk, however. While a company or entity’s potential value is limitless, that value could also change in a negative direction, resulting in capital losses for shareholders. If a business goes bankrupt, its shareholders are only entitled to their portion of whatever value remains after the business has paid all of its creditors and fulfilled all of its obligations per the terms of the bankruptcy.

TheStreet Dictionary Terms

Hybrid Securities

Hybrid securities behave like debt securities in some ways and like equity securities in other ways. The most common type of hybrid security is a convertible bond. These behave like bonds in that they involve regular payments, but they differ from bonds in that they can also be converted into a specific number of shares of a stock at the holder’s discretion. Another example is an equity warrant, which is an option issued directly by an entity to its shareholders to buy or sell a security for a specific price on or before a specific date.

Derivative Securities

A derivative is a security whose value is based on a specific asset or group of assets (like a stock or commodity). A derivative usually takes the form of a contract between two parties relating to the purchase or sale of a specific asset or pool of assets. Derivatives are often used by individuals and institutions to mitigate risk, but they can also be used speculatively by investors to make money.

One common derivative is a futures contract, which is an agreement to buy or sell an asset at a pre-determined future date for a specific price. If someone were to purchase a futures contract that entitled them to purchase a bale of hay for $35 dollars in three months, but by the time three months had passed, bales of hay were worth $45, the buyer would realize a $10 gain. Forward contracts behave similarly, but they are more customizable and typically carry more risk for both buyer and seller.

Options contracts are also common. These behave like futures, but instead of the buyer being obligated to purchase or sell a specific security at a specific price at a specific point in time, they simply have the option to do so.

Another common derivative is a swap, which is an agreement between two parties to exchange one cash flow for another. One cash flow is usually fixed (like a fixed interest rate), and the other is usually variable (like a variable interest rate). Sometimes, companies swap loan interest rates in different currencies to take advantage of exchange rates.

Examples of Common Securities by Type

The four types of securities are debt, equity, hybrid, and derivative. 


Corporate bonds

Common stock

Convertible bonds


Government bonds

Preferred stock

Convertible preference shares


Certificates of Deposit

Mutual fund shares

Equity warrants


Some ETF shares

Some ETF shares

Some ETF shares


Graph with "Risk" as the Y axis and "Return" as the X axis showing that bonds and CDs have the lowest risk and return, mutual finds and ETFs have higher risk and return, and individual stocks have even higher risk and return

Debt securities like bonds and CDs are less risky than equity securities like stocks, but equity securities offer higher potential returns. 


This section includes answers to some of the most commonly asked questions about securities and other information that may be helpful.

Are Currencies Like the Dollar Securities?

Technically, no—currencies, in theory, are simply stores of value that individuals and institutions can use to pay for goods and services. In practice, however, currencies can be bought, sold, and traded strategically—much like stocks—by individuals or institutions who wish to speculate about how exchange rates may vary in the future. In other words, the primary purpose of currency is not to act as a security, but many people use it like one.

Are Cryptocurrencies Like Bitcoin Securities?

Again, no—the primary purpose of a cryptocurrency is to be a store of value that is decentralized and independent of a central banking system like the Federal Reserve that can be used to pay for goods and services (just like a fiat currency). In the long term, the crypto community looks to decentralized digital currencies like Bitcoin as an eventual replacement for—or alternative to—traditional currency. That being said, many individuals and institutions use cryptocurrencies like securities by buying, selling, and trading them speculatively for profit without any intention of spending them on goods and services.

Are NFTs (Non-Fungible Tokens) Securities? 

Since NFTs are not typically used to pay for goods or services, and their value depends on what buyers are willing to pay for them at any given time (like a collectible trading card or stock in a company), NFTs behave very similarly to some securities, aside from the fact that they are not traded on exchanges. That being said, they are also used to represent ownership of real and digital products, and in that way, they behave more like certificates of authenticity. Additionally, NFTs cannot be easily mixed with other securities and are not exchanged on most security exchange platforms. Most authorities do not consider them securities, but they exist in somewhat of a gray area, so how they are classified may change in the future.