scalper

1. A market maker who assigns excessive markups or markdowns on security transactions. Such activity is in violation of National Association of Securities Dealers rules.
2. An investment adviser who takes a position in a security before publicly recommending the security for purchase. The scalper then sells the security at a profit after the recommendation has caused investors to buy the security and push its price higher. This type of activity must be disclosed to buyers.
3. An in-and-out trader who attempts to profit on relatively small price changes.
4. An individual who purchases something thought to be in short supply and then attempts to resell it at far above the purchase price: A scalper standing outside the stadium was offering to sell two World Series tickets.