A security is generally a fungible, negotiable financial instrument representing financial value.^[1] Securities are broadly categorized into:

• debt securities (such as banknotes, bonds and debentures),
• equity securities, e.g., common stocks; and,
• derivative contracts, such as forwards, futures, options and swaps.

A debenture is a document that either creates a debt or acknowledges it, and it is a debt without collateral. Incorporate finance, the term is used for a medium- to long-term debt instrument used by large companies to borrow money. In some countries the term is used interchangeably with bond, loan stock or note. A debenture is thus like a certificate of loan or a loan bond evidencing the fact that the company is liable to pay a specified amount with interest and although the money raised by the debentures becomes a part of the company's capital structure, it does not become share capital.^[1] Senior debentures get paid before subordinate debentures, and there are varying rates of risk and payoff for these categories.

Debentures are generally freely transferable by the debenture holder. Debenture holders have no rights to vote in the company's general meetings of shareholders, but they may have separate meetings or votes e.g. on changes to the rights attached to the debentures. The interest paid to them is a charge against profit in the company's financial statements

Common stock is a form. of corporate equity ownership, a type of security. The terms "voting share" or "ordinary share" are also used in other parts of the world; common stock being primarily used in the United States.

It is called "common" to distinguish it from preferred stock. If both types of stock exist, common stock holders cannot be paid dividends until all preferred stock dividends (including payments in arrears) are paid in full.

In finance, a forward contract or simply a forward is a non-standardized contract between two parties to buy or sell an asset at a specified future time at a price agreed upon today.^[1] This is in contrast to a spot contract, which is an agreement to buy or sell an asset today. The party agreeing to buy the underlying asset in the future assumes a long position, and the party agreeing to sell the asset in the future assumes a short position. The price agreed upon is called the delivery price, which is equal to the forward price at the time the contract is entered into.

In finance, a futures contract is a standardized contract between two parties to buy or sell a specified asset of standardized quantity and quality for a price agreed today (the futures price or strike price) with delivery and payment occurring at a specified future date, the delivery date. The contracts are negotiated at a futures exchange, which acts as an intermediary between the two parties. The party agreeing to buy the underlying asset in the future, the "buyer" of the contract, is said to be "long", and the party agreeing to sell the asset in the future, the "seller" of the contract, is said to be "short". The terminology reflects the expectations of the parties—the buyer hopes or expects that the asset price is going to increase, while the seller hopes or expects that it will decrease in near future.

In many cases, the underlying asset to a futures contract may not be traditional commodities at all – that is, for financial futures the underlying asset or item can be currencies, securities or financial instruments and intangible assets or referenced items such as stock indexes and interest rates.