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 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. In some countries and languages the term "security" is commonly used in day-to-day parlance to mean any form of financial instrument, even though the underlying legal and regulatory regime may not have such a broad definition.
The company or other entity issuing the security is called the issuer. A country's regulatory structure determines what qualifies as a security. For example, private investment pools may have some features of securities, but they may not be registered or regulated as such if they meet various restrictions.
Securities are the traditional way that commercial enterprises raise new capital. These may be an attractive alternative to bank loans depending on their pricing and market demand for particular characteristics. Another disadvantage of bank loans as a source of financing is that the bank may seek a measure of protection against default by the borrower via extensive financial covenants. Through securities, capital is provided by investors who purchase the securities upon their initial issuance. In a similar way, a government may issue securities too when it needs to increase government debt.
The traditional economic function of the purchase of securities is investment, with the view to receiving income or achieving capital gain. Debt securities generally offer a higher rate of interest than bank deposits, and equities may offer the prospect of capital growth. Equity investment may also offer control of the business of the issuer. Debt holdings may also offer some measure of control to the investor if the company is a fledgling start-up or an old giant undergoing 'restructuring'. In these cases, if interest payments are missed, the creditors may take control of the company and liquidate it to recover some of their investment.
Collateral and sources of collateral are changing, in 2012 gold became a more acceptable form of collateral. However more recently Exchange-traded funds (ETFs) seen by many as the ugly ducklings of the collateral world have started to become more readily available and acceptable. But in a world where collateral is becoming scarce and efficiency is everything, many of these mallards are proving themselves to be not so ugly after all´many more are veritable swans. The problem, until now, for collateral managers has been deciphering the bad eggs from the good, which proves to be a time consuming and inefficient task.
Money market instruments are short term debt instruments that may have characteristics of deposit accounts, such as certificates of deposit, Accelerated Return Notes (ARN), and certain bills of exchange. They are highly liquid and are sometimes referred to as "near cash". Commercial paper is also often highly liquid.
Government bonds are medium or long term debt securities issued by sovereign governments or their agencies. Typically they carry a lower rate of interest than corporate bonds, and serve as a source of finance for governments. U.S. federal government bonds are called treasuries. Because of their liquidity and perceived low risk, treasuries are used to manage the money supply in the open market operations of non-US central banks.
Convertibles are bonds or preferred stock that can be converted, at the election of the holder of the convertibles, into the common stock of the issuing company. The convertibility, however, may be forced if the convertible is a callable bond, and the issuer calls the bond. The bondholder has about 1 month to convert it, or the company will call the bond by giving the holder the call price, which may be less than the value of the converted stock. This is referred to as a forced conversion.
Public securities markets are either primary or secondary markets. In the primary market, the money for the securities is received by the issuer of the securities from investors, typically in an initial public offering (IPO). In the secondary market, the securities are simply assets held by one investor selling them to another investor, with the money going from one investor to the other.
Growth in informal electronic trading systems has challenged the traditional business of stock exchanges. Large volumes of securities are also bought and sold "over the counter" (OTC). OTC dealing involves buyers and sellers dealing with each other by telephone or electronically on the basis of prices that are displayed electronically, usually by financial data vendors such as SuperDerivatives, Reuters, Investing.com and Bloomberg.