The stock or capital stock of a business entity represents the original capital paid into or invested in the business by its founders. It serves as a security for the creditors of a business since it cannot be withdrawn to the detriment of the creditors. Stock is distinct from the property and the assets of a business which may fluctuate in quantity and value.

A stock market or equity market is a public market (a loose network of economic transactions, not a physical facility or discrete entity) for the trading of company stock and derivatives 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 was estimated at about $36.6 trillion US at the beginning of October 2008.[1] The total world derivatives market has been estimated at about $791 trillion face or nominal value,[2] 11 times the size of the entire world economy.[3] The value of the derivatives market, because it is stated in terms of notional values, cannot be directly compared to a stock or a fixed income security, which traditionally refers to an actual value. Moreover, the vast majority of derivatives 'cancel' each other out (i.e., a derivative 'bet' on an event occurring is offset by a comparable derivative 'bet' on the event not occurring). 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 of a corporation or mutual organization specialized in the business of bringing buyers and sellers of the organizations to a listing of stocks and securities together. The largest stock market in the United States, by market cap, is the New York Stock Exchange, NYSE. In Canada, the largest stock market is the Toronto Stock Exchange. Major European examples of stock exchanges include the London Stock Exchange, Paris Bourse, and the Deutsche Börse. Asian examples include the Tokyo Stock Exchange, the Hong Kong Stock Exchange, the Shanghai Stock Exchange, and the Bombay Stock Exchange. In Latin America, there are such exchanges as the BM&F Bovespa and the BMV.

A stock trader or a stock investor is an individual or firm who buys and sells stocks or bonds (and possibly other financial assets) in the financial markets. Individuals or firms trading equity (stock) on the stock markets as their principal capacity are called stock traders. Stock traders usually try to profit from short-term price volatility with trades lasting anywhere from several seconds to several weeks. The stock trader is usually a professional. Persons can call themselves full or part-time stock traders/investors while maintaining other professions. When a stock trader/investor has clients, and acts as a money manager or adviser with the intention of adding value to their clients finances, he is also called a financial advisor or manager. In this case, the financial manager could be an independent professional or a large bank corporation employee. This may include managers dealing with investment funds, hedge funds, mutual funds, and pension funds, or other professionals in equity investment, fund management, and wealth management. Several different types of stock trading exist including day trading, trend following, market making, scalping (trading), momentum trading, trading the news, and arbitrage.

On the other hand, stock investors are firms or individuals who purchase stocks with the intention of holding them for an extended period of time, usually several months to years. They rely primarily on fundamental analysis for their investment decisions and fully recognize stock shares as part-ownership in the company. Many investors believe in the buy and hold strategy, which as the name suggests, implies that investors will buy stock ownership in a corporation and hold onto those stocks for the very long term, generally measured in years. This strategy was made popular in the equity bull market of the 1980s and 90s where buy-and-hold investors rode out short-term market declines and continued to hold as the market returned to its previous highs and beyond. However, during the 2001-2003 equity bear market, the buy-and-hold strategy lost some followers as broader market indexes like the NASDAQ saw their values decline by over 60%

TRADERS

Merchant, retailer or one who attempts to generally buy wholesale and sell later at a profit

A merchant is a businessman who trades in commodities that he did not produce himself, in order to earn a profit.

Merchants can be one of two types:

A wholesale merchant operates in the chain between producer and retail merchant. Some wholesale merchants only organize the movement of goods rather than move the goods themselves.

A retail merchant or retailer sells commodities to consumers (including businesses). A shop owner is a retail merchant.

Trader (finance), someone who buys and sells financial instruments such as stocks, bonds, derivatives, etc

In finance, a trader is someone who buys and sells financial instruments such as stocks, bonds, commodities and derivatives. A broker who simply fills buy or sell orders is not a trader, as they are merely executing instructions given to them.

Traders are either professionals working in a financial institution or a corporation, or individual investors, or day traders. They buy and sell financial instruments traded in the stock markets, derivatives markets and commodity markets, comprising the stock exchanges, derivatives exchanges and the commodities exchanges. Several categories and designations for diverse kinds of traders are found in finance