Short-term trading where the same security is bought and sold within a short period of time, such as a day, a week or a month. In-and-out traders hope to profit from day-to-day price fluctuations and are not usually interested in long-term growth. Day trading, a speculative, highly risky form of trading, falls into this category. During the market frenzy of technology stocks in 1999, many day traders speculated on the gains of hot tech stocks — hour to hour, and even minute to minute.