Insider Trading
nsider trading is the trading of a public company's stock or other securities(such as bonds or stock options) by individuals with access to non-public information about the company. In most countries, trading by corporate insiders such as officers, key employees, directors, and large shareholders may be legal, if this trading is done in a way that does not take advantage of non-public information.
However, the term is frequently used to refer to a practice 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 in breach of a fiduciary or other relationship of trust and confidence or where the non-public information was misappropriated from the company.
https://en.wikipedia.org/wiki/Insider_trading#Illegal_insider_trading