Scalping

Scalping is a name given to a investment system to buy and sell quickly, typically at only a few cents higher than the original price paid.

This is a trading strategy that seeks to accumulate multiple profits on tiny price changes.  By placing from 10 to several hundred trades in a single day, the investor hopes that small movements in prices are much easier to catch than overall large gains.  Scalpers use this to gain a profit even when the bid/ask prices fail to budge and they must move quickly, with only minutes or seconds to act.  Occasionally called market makers or specialists, scalpers protect the liquidity and flow of products to the market.