Recent Developments Regarding the Misappropriation Theory in Securities Fraud Actions

On 25th June, 1997, the US Supreme Court issued an important decision in which it endorsed an expanded theory of insider trading liability under the federal securities laws. In United States v O'Hagan, the Court held, in a 6‐3 decision, that a person who misappropriates confidential information for securities trading purposes, in breach of a duty owed to the source of the information, may be found liable for securities fraud under s. 10(b) of the Securities Exchange Act of 1934 (the ‘Exchange Act’) and SEC Rule 10b‐5, which prohibit the use of fraud or deception ‘in connection with the purchase or sale of any security’. In endorsing the ‘misappropriation’ theory, the Court resolved a longstanding split among the federal Circuit Courts of Appeal and upheld an important tool in the prosecution of securities fraud. Separately, the Court held that the Securities and Exchange Commission (SEC) did not exceed its rulemaking authority under s. 14(e) of the Exchange Act when it adopted Rule 14e‐3(a), which prohibits trading on the basis of material, non‐public information concerning a tender offer, without requiring the government to show a breach of fiduciary duty.