insider
n. someone who has a position in a business or stock brokerage, which allows him/her to be privy to confidential information (such as future changes in management, upcoming profit and loss reports, secret sales figures and merger negotiations) which will affect the value of stocks or bonds. While there is nothing wrong with being an insider, use of the confidential information unavailable to the investing public in order to profit through sale or purchase of stocks or bonds is unethical and a crime under the Securities and Exchange Act.