426 U.S. 438 (U.S. 1976)
TSC Industries v. Northway is a cornerstone of securities law that calibrates the disclosure obligations of issuers when soliciting proxies from shareholders.
What is the proper standard of materiality for alleged omissions or misstatements in proxy solicitations under Section 14(a) of the Securities Exchange Act and SEC Rule 14a-9?
An omitted fact is material if there is a substantial likelihood that a reasonable shareholder would consider it important in deciding how to vote. Put another way, there must be a substantial likelihood that the disclosure of the omitted fact would have been viewed by the reasonable investor as having significantly altered the total mix of information made available. The standard rejects both (1) a minimal 'might have been considered important' threshold and (2) an outcome-determinative 'would have changed the vote' test.
The Court rejected the Seventh Circuit's 'might have been considered important' standard and adopted the 'substantial likelihood'/'total mix' materiality test for Rule 14a-9 proxy cases. The judgment of the court of appeals was reversed and the case remanded for application of the proper standard.
TSC Industries v. Northway established the governing materiality standard for proxy disclosures and profoundly influenced federal securities law. Its 'substantial likelihood' and 'total mix' formulation remains the touchstone in Section 14(a) litigation and was later adopted in Rule 10b-5 cases, most notably in Basic v. Levinson. The decision guides courts in managing summary judgment and trial in disclosure suits and instructs issuers that the point of disclosure is decision-useful information for a reasonable shareholder—not exhaustive cataloging of every tangential detail. For law students, TSC is essential for exams and practice because it provides the template for analyzing whether an omission or misstatement crosses the line into materiality across multiple securities regimes.