Day trading is speculation in securities, specifically buying and selling financial instruments within the same trading day. Strictly, day trading is trading only within a day, such that all positions are closed before the market close for the trading day. Many traders may not be so strict or may have day trading as one component of an overall strategy. Traders who participate in day trading are called day traders. Traders who trade in this capacity with the motive of profit are therefore speculators.
Some of the more commonly day-traded financial instruments are stocks, options, currencies, and a host of futures contracts such as equity index futures, interest rate futures, and commodity futures.
Day trading was once an activity that was exclusive to financial firms and professional speculators. Many day traders are bank or investment firm employees working as specialists in equity investment and fund management. However, with the advent of electronic trading and margin trading, day trading has become increasingly popular among at-home traders.
Following the 1987 stock market crash, the SEC adopted "Order Handling Rules" which required market-makers to publish their best bid and ask on the NASDAQ. Another reform made was the "Small Order Execution System", or "SOES", which required market makers to buy or sell, immediately, small orders (up to 1000 shares) at the market-makers listed bid or ask. The design of the system gave rise to arbitrage by a small group of traders known as the "SOES bandits", who made sizable profits buying and selling small orders to market makers by anticipating price moves before they were reflected in the published inside bid/ask prices. The SOES system ultimately led to trading facilitated by software instead of market makers via electronic communications networks ("ECNs").
In the late 1990s, existing ECNs began to offer their services to small investors. New brokerage firms which specialized in serving online traders who wanted to trade on the ECNs emerged. New ECNs also arose, most importantly Archipelago ("arca") and Island ("isld"). Archipelago eventually became a stock exchange and in 2005 was purchased by the NYSE. (At this time, the NYSE has proposed merging Archipelago with itself, although some resistance has arisen from NYSE members.) Commissions plummeted. To give an extreme example (trading 1000 shares of Google), an online trader in 2005 might have bought $300,000 of stock at a commission of about $10, compared to the $3,000 commission the trader would have paid in 1974. Moreover, the trader was able in 2005 to buy the stock almost instantly and got it at a cheaper price.
ECNs are in constant flux. New ones are formed, while existing ones are bought or merged. As of the end of 2006, the most important ECNs to the individual trader were:
Instinet (which bought Island in 2002),
Archipelago (although technically it is now an exchange rather than an ECN),
the Brass Utility ("brut"), and
the SuperDot electronic system now used by the NYSE.
This combination of factors has made day trading in stocks and stock derivatives (such as ETFs) possible. The low commission rates allow an individual or small firm to make a large number of trades during a single day. The liquidity and small spreads provided by ECNs allow an individual to make near-instantaneous trades and to get favorable pricing. High-volume issues such as Intel or Microsoft generally have a spread of only $0.01, so the price only needs to move a few pennies for the trader to cover his commission costs and show a profit.
The ability for individuals to day trade coincided with the extreme bull market in technological issues from 1997 to early 2000, known as the Dot-com bubble. From 1997 to 2000, the NASDAQ rose from 1200 to 5000. Many naive investors with little market experience made huge profits buying these stocks in the morning and selling them in the afternoon, at 400% margin rates.
In March, 2000, this bubble burst, and a large number of less-experienced day traders began to lose money as fast, or faster, than they had made during the buying frenzy. The NASDAQ crashed from 5000 back to 1200; many of the less-experienced traders went broke, although obviously it was possible to have made a fortune during that time by shorting or playing on volatility.