This strategy is mostly only done by day traders. It requires that you have access to one to several real-time news sources and can make split second decisions. News and rumors can provide large amounts of volatility and high emotion creating great opportunities if traded properly. The biggest challenge of trading this strategy is anticipating the market’s reaction to the news and how it effects the price of the stock. Click here for more information on trading news and rumors.
The second type of scalping is done by purchasing a large number of shares that are sold for a gain on a very small price movement. A trader of this style will enter into positions for several thousand shares and wait for a small move, which is usually measured in cents. Such an approach requires highly liquid stock to allow for entering and exiting 3,000 to 10,000 shares easily.
Smaller moves, easier to obtain - A change in price results from imbalance of buying and selling powers. Most of the time within a day, prices stay stable, moving within a small range. This means neither buying nor selling power control the situation. There are only a few times which price moves towards one direction, i.e. either buying or selling power controls the situation. It requires bigger imbalances for bigger price changes. It is what scalpers look for - capturing smaller moves which happen most of the time, as opposed to larger ones.

This often means trading shares of companies that have just released breaking news, reported earnings, or have another fundamental catalyst that is resulting in above average retail interest. The type of stocks a day trader will focus on are typically much different from what a long term investor would look for. Day traders acknowledge the high levels of risk associated with trading volatile markets and they mitigate those risks by holding positions for very short periods of time.
Day trading is not for everyone and involves significant risks. Moreover, it requires an in-depth understanding of how the markets work and various strategies for profiting in the short term. While we remember the success stories of those who struck it rich as a day trader, remember that most do not—many will fizzle out and many will just barely stay afloat. Furthermore, don't underestimate the role that luck and good timing play—while skill is certainly an element, a rout of bad luck can sink even the most experienced day trader.
Successful traders have to move fast, but they don't have to think fast. Why? Because they've developed a trading strategy in advance, along with the discipline to stick to that strategy. It is important to follow your formula closely rather than try to chase profits. Don't let your emotions get the best of you and abandon your strategy. There's a mantra among day traders: "Plan your trade and trade your plan."