By providing a ready market for the exchange of securities, stock exchanges greatly facilitate the financing of business through flotation of stocks and bonds. However, speculation in stocks can sometimes accentuate the instability of an economy. The reality of the Great Depression was emphasized by the stock market crash in 1929. The interstate sale of securities and certain stock exchange practices in the United States are regulated by federal laws administered by the Securities and Exchange Commission. Today, a large percentage of stocks are traded through such over-the-counter organizations as NASDAQ (National Association of Securities Dealers Automatic Quotations) and its European equivalent, NASDAQ Europe (formerly Easdaq). Through these organizations, many securities not listed on a major stock exchange may be traded by dealers using computer and telecommunications technology; in 1994, NASDAQ, on which many computer and other high-technology stocks are traded, surpassed the NYSE in annual share volume. After the deregulation of the British securities market in 1986, the London Stock Exchange saw a decline in business due to a new computerized market similar to NASDAQ. The 21st cent. has seen the mergers of many stock exchanges, such as those that created Euronext in 2000 from the Amsterdam, Brussels, and Paris exchanges, expanded it in subsequent years, and brought it and the NYSE into NYSE Euronext, Inc., in 2007. Intercontinentcal Exchange (ICE), an exchange and clearinghouse network focused on commodities futures and options, purchased NYSE Euronext in 2012, and sold off Euronext in 2014. The stocks of public companies are also traded outside exchanges on such alternative trading systems as electronic communication networks.
Computer-driven trading has significantly affected the stock exchange. Computer and telecommunications technology, besides opening a wide market in over the counter dealings, has also given rise to trading on an international level. Networked computers allow trading to occur around the clock (after-hours NYSE and NASDAQ trading began in 1999), and the securities trading on one major stock exchange can now significantly affect the trading on others. Technology also now allows for “day trading,” a high-risk business in which numerous computerized trades are made during a single day, with large gains (and large losses) possible.
Another form of computerized trading is high-frequency trading, in which computer programs analyze the market and execute trades at high speed to reap momentary financial benefits. Such trades often involve very small gains that are magnified by the amount of shares traded and the number of trades made. Traders engaged in high-frequency trading are typically employed by well-capitalized firms and hold shares for brief periods of time, usually selling all shares by the end of a trading day. High-frequency trading firms have also used early access to information concerning orders for stock, often provided the stock exchanges, to profit on such orders, an approach that has been widely criticized. A majority of all trades are now excecuted by high-frequency traders. As a result of these and other changes, many contend that the traditional manner of trading will eventually become obsolete. The increasing volatility of the stock exchanges in the early 21st cent. and the drop in the number of private companies going public has led to the development of private stock exchanges where the shares of private companies may be traded under restricted terms.
See also margin requirement.
See A. Crump,
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2023, Columbia University Press. All rights reserved.
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