The misappropriation theory of insider trading is a form of insider trading where an individual trades stock in a corporation, with whom they are unaffiliated, on the basis of material non-public information they obtained through a breach of a fiduciary duty owed to the source of the information. Opposed to the classical theory of insider trading, the misappropriation theory of insider trading does not require that the seller owes a fiduciary duty to the company in whose stock they trade. The seller’s knowledge of insider information alone is sufficient to create liability under Rule 10b-5.
Before U.S. v. O’Hagan, 521 U.S. 642 (1997), individuals could only be liable for insider trading under the classical theory of insider trading. In U.S. v. O’Hagan, the U.S. Supreme Court faced a scenario where a partner at a large law firm purchased stock futures in a company conducting a tender offer based on inside information that he gleaned from other partners at the firm working on the deal. Although the partner had no fiduciary duty to the companies in whose stock he traded, the Supreme Court found him liable under Rule 10 b-5 on the grounds that he used confidential information to trade securities. The Court reasoned that such insider trading is fraudulent because it is akin to embezzlement; that is, the owner of the confidential information has exclusive use of such information, and the trader misappropriates that information by trading on it and not disclosing the use of the information to the owner of the information.
[Last updated in January of 2022 by the Wex Definitions Team]