A stock market, or (equity market), is a private or public market for the trading of company stock and derivatives of company stock at an agreed price; these are securities listed on a stock exchange as well as those only traded privately.
The size of the world stock market is estimated at about $36.6 trillion USD at the beginning of October 2008 . The world derivatives market has been estimated at about $480 trillion face or nominal value, 12 times the size of the entire world economy. It must be noted though that the value of the derivatives market, because it is stated in terms of notional values, and cannot be directly compared to a stock or a fixed income security, which traditionally refers to an actual value. Many such relatively illiquid securities are valued as marked to model, rather than an actual market price.
The stocks are listed and traded on stock exchanges which are entities a corporation or mutual organization specialized in the business of bringing buyers and sellers of stocks and securities together. The stock market in the United States includes the trading of all securities listed on the NYSE, the NASDAQ, the Amex, as well as on the many regional exchanges, e.g. OTCBB and Pink Sheets. European examples of stock exchanges include the London Stock Exchange, the Deutsche Börse and the Paris Bourse, now part of Euronext.
Participants in the stock market range from small individual stock investors to large hedge fund traders, who can be based anywhere. Their orders usually end up with a professional at a stock exchange, who executes the order.
Some exchanges are physical locations where transactions are carried out on a trading floor, by a method known as open outcry. This type of auction is used in stock exchanges and commodity exchanges where traders may enter "verbal" bids and offers simultaneously. The other type of stock exchange is a virtual kind, composed of a network of computers where trades are made electronically via traders.
Actual trades are based on an auction market paradigm where a potential buyer bids a specific price for a stock and a potential seller asks a specific price for the stock. (Buying or selling at market means you will accept any ask price or bid price for the stock, respectively.) When the bid and ask prices match, a sale takes place on a first come first served basis if there are multiple bidders or askers at a given price.
The purpose of a stock exchange is to facilitate the exchange of securities between buyers and sellers, thus providing a marketplace (virtual or real). The exchanges provide real-time trading information on the listed securities, facilitating price discovery.
The New York Stock Exchange is a physical exchange, also referred to as a listed exchange — only stocks listed with the exchange may be traded. Orders enter by way of exchange members and flow down to a specialist, who goes to the floor trading post to trade stock. The specialist's job is to match buy and sell orders using open outcry. If a spread exists, no trade immediately takes place--in this case the specialist should use his/her own resources (money or stock) to close the difference after his/her judged time. Once a trade has been made the details are reported on the "tape" and sent back to the brokerage firm, which then notifies the investor who placed the order. Although there is a significant amount of human contact in this process, computers play an important role, especially for so-called "program trading".
The NASDAQ is a virtual listed exchange, where all of the trading is done over a computer network. The process is similar to the New York Stock Exchange. However, buyers and sellers are electronically matched. One or more NASDAQ market makers will always provide a bid and ask price at which they will always purchase or sell 'their' stock.
The Paris Bourse, now part of Euronext, is an order-driven, electronic stock exchange. It was automated in the late 1980s. Prior to the 1980s, it consisted of an open outcry exchange. Stockbrokers met on the trading floor or the Palais Brongniart. In 1986, the CATS trading system was introduced, and the order matching process was fully automated.
From time to time, active trading (especially in large blocks of securities) have moved away from the 'active' exchanges. Securities firms, led by UBS AG, Goldman Sachs Group Inc. and Credit Suisse Group, already steer 12 percent of U.S. security trades away from the exchanges to their internal systems. That share probably will increase to 18 percent by 2010 as more investment banks bypass the NYSE and NASDAQ and pair buyers and sellers of securities themselves, according to data compiled by Boston-based Aite Group LLC, a brokerage-industry consultant .
Now that computers have eliminated the need for trading floors like the Big Board's, the balance of power in equity markets is shifting. By bringing more orders in-house, where clients can move big blocks of stock anonymously, brokers pay the exchanges less in fees and capture a bigger share of the $11 billion a year that institutional investors pay in trading commissions .
However, corporate governance (at least in the West) has been very much adversely affected by the rise of (largely 'absentee') institutional 'owners'.
In the middle of the 13th century, Venetian bankers began to trade in government securities. In 1351 the Venetian government outlawed spreading rumors intended to lower the price of government funds. Bankers in Pisa, Verona, Genoa and Florence also began trading in government securities during the 14th century. This was only possible because these were independent city states not ruled by a duke but a council of influential citizens. The Dutch later started joint stock companies, which let shareholders invest in business ventures and get a share of their profits - or losses. In 1602, the Dutch East India Company issued the first shares on the Amsterdam Stock Exchange. It was the first company to issue stocks and bonds.
The Amsterdam Stock Exchange (or Amsterdam Beurs) is also said to have been the first stock exchange to introduce continuous trade in the early 17th century. The Dutch "pioneered short selling, option trading, debt-equity swaps, merchant banking, unit trusts and other speculative instruments, much as we know them" (Murray Sayle, "Japan Goes Dutch", London Review of Books XXIII.7, April 5, 2001). There are now stock markets in virtually every developed and most developing economies, with the world's biggest markets being in the United States, Canada, China (Hongkong), India, UK, Germany, France and Japan.
Exchanges also act as the clearinghouse for each transaction, meaning that they collect and deliver the shares, and guarantee payment to the seller of a security. This eliminates the risk to an individual buyer or seller that the counterparty could default on the transaction.
The smooth functioning of all these activities facilitates economic growth in that lower costs and enterprise risks promote the production of goods and services as well as employment. In this way the financial system contributes to increased prosperity.
The financial system in most western countries has undergone a remarkable transformation. One feature of this development is disintermediation. A portion of the funds involved in saving and financing flows directly to the financial markets instead of being routed via the traditional bank lending and deposit operations. The general public's heightened interest in investing in the stock market, either directly or through mutual funds, has been an important component of this process. Statistics show that in recent decades shares have made up an increasingly large proportion of households' financial assets in many countries. In the 1970s, in Sweden, deposit accounts and other very liquid assets with little risk made up almost 60 percent of households' financial wealth, compared to less than 20 percent in the 2000s. The major part of this adjustment in financial portfolios has gone directly to shares but a good deal now takes the form of various kinds of institutional investment for groups of individuals, e.g., pension funds, mutual funds, hedge funds, insurance investment of premiums, etc. The trend towards forms of saving with a higher risk has been accentuated by new rules for most funds and insurance, permitting a higher proportion of shares to bonds. Similar tendencies are to be found in other industrialized countries. In all developed economic systems, such as the European Union, the United States, Japan and other developed nations, the trend has been the same: saving has moved away from traditional (government insured) bank deposits to more risky securities of one sort or another.
Riskier long-term saving requires that an individual possess the ability to manage the associated increased risks. Stock prices fluctuate widely, in marked contrast to the stability of (government insured) bank deposits or bonds. This is something that could affect not only the individual investor or household, but also the economy on a large scale. The following deals with some of the risks of the financial sector in general and the stock market in particular. This is certainly more important now that so many newcomers have entered the stock market, or have acquired other 'risky' investments (such as 'investment' property, i.e., real estate and collectables).
With each passing year, the noise level in the stock market rises. Television commentators, financial writers, analysts, and market strategists are all overtaking each other to get investors' attention. At the same time, individual investors, immersed in chat rooms and message boards, are exchanging questionable and often misleading tips. Yet, despite all this available information, investors find it increasingly difficult to profit. Stock prices skyrocket with little reason, then plummet just as quickly, and people who have turned to investing for their children's education and their own retirement become frightened. Sometimes there appears to be no rhyme or reason to the market, only folly.
This is a quote from the preface to a published biography about the long-term value-oriented stock investor Warren Buffett. Buffett began his career with $100, and $105,000 from seven limited partners consisting of Buffett's family and friends. Over the years he has built himself a multi-billion-dollar fortune. The quote illustrates some of what has been happening in the stock market during the end of the 20th century and the beginning of the 21st.
From experience we know that investors may temporarily pull financial prices away from their long term trend level. Over-reactions may occur—so that excessive optimism (euphoria) may drive prices unduly high or excessive pessimism may drive prices unduly low. New theoretical and empirical arguments have been put forward against the notion that financial markets are efficient.
According to the efficient market hypothesis (EMH), only changes in fundamental factors, such as profits or dividends, ought to affect share prices. (But this largely theoretic academic viewpoint also predicts that little or no trading should take place—contrary to fact—since prices are already at or near equilibrium, having priced in all public knowledge.) But the efficient-market hypothesis is sorely tested by such events as the stock market crash in 1987, when the Dow Jones index plummeted 22.6 percent—the largest-ever one-day fall in the United States. This event demonstrated that share prices can fall dramatically even though, to this day, it is impossible to fix a definite cause: a thorough search failed to detect any specific or unexpected development that might account for the crash. It also seems to be the case more generally that many price movements are not occasioned by new information; a study of the fifty largest one-day share price movements in the United States in the post-war period confirms this. Moreover, while the EMH predicts that all price movement (in the absence of change in fundamental information) is random (i.e., non-trending), many studies have shown a marked tendency for the stock market to trend over time periods of weeks or longer.
Various explanations for large price movements have been promulgated. For instance, some research has shown that changes in estimated risk, and the use of certain strategies, such as stop-loss limits and Value at Risk limits, theoretically could cause financial markets to overreact.
Other research has shown that psychological factors may result in exaggerated stock price movements. Psychological research has demonstrated that people are predisposed to 'seeing' patterns, and often will perceive a pattern in what is, in fact, just noise. (Something like seeing familiar shapes in clouds or ink blots.) In the present context this means that a succession of good news items about a company may lead investors to overreact positively (unjustifiably driving the price up). A period of good returns also boosts the investor's self-confidence, reducing his (psychological) risk threshold.
Another phenomenon—also from psychology—that works against an objective assessment is group thinking. As social animals, it is not easy to stick to an opinion that differs markedly from that of a majority of the group. An example with which one may be familiar is the reluctance to enter a restaurant that is empty; people generally prefer to have their opinion validated by those of others in the group.
In one paper the authors draw an analogy with gambling. In normal times the market behaves like a game of roulette; the probabilities are known and largely independent of the investment decisions of the different players. In times of market stress, however, the game becomes more like poker (herding behavior takes over). The players now must give heavy weight to the psychology of other investors and how they are likely to react psychologically.
The stock market, as any other business, is quite unforgiving of amateurs. Inexperienced investors rarely get the assistance and support they need. In the period running up to the recent Nasdaq crash, less than 1 percent of the analyst's recommendations had been to sell (and even during the 2000 - 2002 crash, the average did not rise above 5%). The media amplified the general euphoria, with reports of rapidly rising share prices and the notion that large sums of money could be quickly earned in the so-called new economy stock market. (And later amplified the gloom which descended during the 2000 - 2002 crash, so that by summer of 2002, predictions of a DOW average below 5000 were quite common.)
Over the short-term, stocks and other securities can be battered or buoyed by any number of fast market-changing events, making the stock market difficult to predict.
A stock market crash is often defined as a sharp dip in share prices of equities listed on the stock exchanges. In parallel with various economic factors, a reason for stock market crashes is also due to panic. Often, stock market crashes end speculative economic bubbles.
There have been famous stock market crashes that have ended in the loss of billions of dollars and wealth destruction on a massive scale. An increasing number of people are involved in the stock market, especially since the social security and retirement plans are being increasingly privatized and linked to stocks and bonds and other elements of the market. There have been a number of famous stock market crashes like the Wall Street Crash of 1929, the stock market crash of 1973–4, the Black Monday of 1987, the Dot-com bubble of 2000.
One of the most famous stock market crashes started October 24, 1929 on Black Thursday. The Dow Jones Industrial lost 50% during this stock market crash. It was the beginning of the Great Depression. Another famous crash took place on October 19, 1987 – Black Monday. On Black Monday itself, the Dow Jones fell by 22.6% after completing a 5 year continuous rise in share prices. This event not only shook the USA, but quickly spread across the world. Thus, by the end of October, stock exchanges in Australia lost 41.8%, in Canada lost 22.5%, in Hong Kong lost 45.8%, and in Great Britain lost 26.4%. The names “Black Monday” and “Black Tuesday” are also used for October 28-29, 1929, which followed Terrible Thursday--the starting day of the stock market crash in 1929. The crash in 1987 raised some puzzles-–main news and events did not predict the catastrophe and visible reasons for the collapse were not identified. This event raised questions about many important assumptions of modern economics, namely, the theory of rational human conduct, the theory of market equilibrium and the hypothesis of market efficiency. For some time after the crash, trading in stock exchanges worldwide was halted, since the exchange computers did not perform well owing to enormous quantity of trades being received at one time. This halt in trading allowed the Federal Reserve system and central banks of other countries to take measures to control the spreading of worldwide financial crisis. In the United States the SEC introduced several new measures of control into the stock market in an attempt to prevent a re-occurrence of the events of Black Monday. Computer systems were upgraded in the stock exchanges to handle larger trading volumes in a more accurate and controlled manner. The SEC modified the margin requirements in an attempt to lower the volatility of common stocks, stock options and the futures market. The New York Stock Exchange and the Chicago Mercantile Exchange introduced the concept of a circuit breaker. The circuit breaker halts trading if the Dow declines a prescribed number of points for a prescribed amount of time.
The movements of the prices in a market or section of a market are captured in price indices called stock market indices, of which there are many, e.g., the S&P, the FTSE and the Euronext indices. Such indices are usually market capitalization weighted, with the weights reflecting the contribution of the stock to the index. The constituents of the index are reviewed frequently to include/exclude stocks in order to reflect the changing business environment.
Financial innovation has brought many new financial instruments whose pay-offs or values depend on the prices of stocks. Some examples are exchange-traded funds (ETFs), stock index and stock options, equity swaps, single-stock futures, and stock index futures. These last two may be traded on futures exchanges (which are distinct from stock exchanges—their history traces back to commodities futures exchanges), or traded over-the-counter. As all of these products are only derived from stocks, they are sometimes considered to be traded in a (hypothetical) derivatives market, rather than the (hypothetical) stock market.
Global issuance of equity and equity-related instruments totaled $505 billion in 2004, a 29.8% increase over the $389 billion raised in 2003. Initial public offerings (IPOs) by US issuers increased 221% with 233 offerings that raised $45 billion, and IPOs in Europe, Middle East and Africa (EMEA) increased by 333%, from $ 9 billion to $39 billion.
Additionally, many choose to invest via the index method. In this method, one holds a weighted or unweighted portfolio consisting of the entire stock market or some segment of the stock market (such as the S&P 500 or Wilshire 5000). The principal aim of this strategy is to maximize diversification, minimize taxes from too frequent trading, and ride the general trend of the stock market (which, in the U.S., has averaged nearly 10%/year, compounded annually, since World War II).