After-Hours Trading
The buying and selling of stock outside normal trading hours (weekdays, 9:30 a.m. to 4 p.m. E.T. for the New York Stock Exchange). The best-known after-hours market is the electronic system Instinet. Although after-hours trades seem to foreshadow some sleepless, globally connected digital nervous system, the relatively light volume of Instinet trading is evidence that even stock traders need their daily downtime. The popularity of online trading may change this, but right now the small number of trades makes Instinet prices fickle, even though they are regularly cited to predict where a stock is expected to open during normal trading hours.

Analyst Recommendation
A professional opinion to buy or sell a stock. Banks and brokers employ armies of research analysts to track specific industries and stocks. Their expertise helps inform decisions about partners and investments, but it is also a sales tool for promoting decisions that have already been made. Online investing helped open access to analyst reports the same way it leveled the playing field for IPOs and real-time quotes (see below). But be wary of any analyst who recommends a company that has been underwritten by the analyst's bank; also, understand analyst euphemisms such as "hold," which almost always means "sell." Respected analysts who can move the price of a stock just by issuing a report or adjusting an earnings estimate are called axes.

Capital-Gains Tax
The government's share of your investment prowess. The tax is skewed to discourage the kind of itchy-trigger, short-term trading the Internet seems to make irresistible. It applies only to actual sales (not "paper profits"), and the tax rate is lower if you wait at least a year before taking the gain (gain being the difference between where you sell and the "cost basis," or what you paid). The top long-term capital-gains rate is 20%, but short-term sales are taxed just like income and can run twice that amount. The difference can sometimes make investors hold stock even when they think it's going down, merely because they don't want to pay the extra tax. Your tax bill is based on total gains, so there's often a lot of tax-loss selling at the end of the year, as losers are dumped to offset winners or other income. (Some traders try to profit from this, buying beaten-down stocks in the hope that the "January effect"--when new money tends to come into the stock market--will create some short-term gains of its own.)