This page explains the five basic characteristics (or parameters) that define each option contract: If you buy an option, you know the underlying asset, whether it`s a call or a put, its exercise price, the expiry date and whether it`s a U.S. or European option. You can be sure that these properties will remain as they are for the whole time that you will keep the option. The most common way to trade options is to switch standardized options contracts that are listed by different futures and options exchanges.  Offers and prices are tracked and can be followed by a ticker symbol. By publishing live markets continuously for option prices, an exchange allows independent parties to conduct price surveys and transactions. As an intermediary for both parts of the transaction include the benefits offered by the Exchange of the transaction: If you purchased the above contract, you would have the right, but not the obligation to purchase shares of Company X in one piece before April 30, 2013. If you decide to exercise your option, you would pay $50 per share and physically own the stock. In the financial field, an option is a contract that gives its owner, the holder, the right, but not the obligation to buy or sell a base asset or a basic instrument at a specified exercise price before or on a specified date, depending on the form of the option. Options are usually acquired by purchase, as a form of compensation or as part of a complex financial transaction. It is therefore also a form of assets and an valuation that may depend on a complex relationship between the base value of the asset, the timing of the asset, market volatility and other factors. Options can be negotiated between private parties in over-the-counter transactions or can be traded on regular over-the-air markets in the form of standardized contracts. The use and popularity of options have increased rapidly in recent decades, and there are a wide range of underlyings for which there are options today.
Perhaps the most well-known underlying assets are individual shares (shares of publicly traded companies). Several short interest rate models (generally applicable to interest rate derivatives) have been developed to evaluate borrowing options. The best known of them are Black-Derman Toy and Hull-White.  These models describe future changes in interest rates in which future changes in the short interest rate are expected.