Glossary

The practice of buying and selling securities during a period of time when the major markets are officially closed. Once reserved for institutional investors, individual investors may now participate. Stocks are traded after hours on ECNs, which match buyers and seller with a computer system in order to execute trades.

An option which can be exercised at any time between the purchase date and the expiration date. Most options in the U.S. are of this type. This is the opposite of a European-style option, which can only be exercised on the date of expiration. Since an American-style option provides an investor with a greater degree of flexibility than a European style option, the premium for an American style option is at least equal to or higher than the premium for a European-style option which otherwise has all the same features. also called American option.

American Stock Exchange. The second-largest stock exchange in the U.S., after the New York Stock Exchange (NYSE). In general, the listing rules are a little more lenient than those of the NYSE, and thus the AMEX has a larger representation of stocks and bonds issued by smaller companies than the NYSE.

The price a seller is willing to accept for a security, also known as the offer price. Along with the price, the ask quote will generally also stipulate the amount of the security willing to be sold at that price.

A condition in which the strike price of an option is equal to (or nearly equal to) the market price of the underlying security.