Insider Trading

illegal stock and securities trading amongst people who have access to private information about a company's financial status

Insider trading is the trading of a corporation's stock or other securities (e.g. bonds or stock options) by corporate insiders such as officers, key employees, directors, or holders of more than ten percent of the firm's shares. Insider trading may be perfectly legal, but the term is frequently used to refer to a practice, illegal in many jurisdictions, in which an insider or a related party trades based on material non-public information obtained during the performance of the insider's duties at the corporation, or otherwise misappropriated.
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Noun
1. buying or selling corporate stock by a corporate officer or other insider on the basis of information that has not been made public and is supposed to remain confidential
(hypernym) trading

Trading by officers, directors, major stockholders, or others who hold private inside information  allowing them to benefit from buying or selling stock.

Participation by corporate officers, directors or employees in the trade of a stock based on confidential or privileged corporate information, knowing that information to be confidential, and seeking thereby to acquire profits or avoid losses on the stock market. - (read more on Insider Trading)