Chiarella v. United States, 445 U.S. 222 (1980), is a case in which the Supreme Court of the United States held that an employee of a printer handling corporate takeover bids who deduced target companies' identities and dealt in their stock without disclosing his knowledge of impending takeovers, had not violated § 10(b) of the Securities Exchange Act of 1934[1] and SEC Rule 10b-5.

After working in a position that gave petitioner Vincent Chiarella inside information on particular corporate takeover bids, the Securities and Exchanges Commission (SEC) investigated his trading activities.

A short time after, he was indicted on seventeen counts of violating the Securities Exchange Act of 1934.

Did Chiaraella "violate Section 10(b) of the 1934 Act by failing to disclose the impending takeover before trading in the target company's securities?

The Court held that "a duty to disclose under section 10(b) does not arise from the mere possession of nonpublic market information."