In the case of Marine Bank v. Weaver, the U.S. Supreme Court ruled in 1981 that a certificate of deposit (CD) issued by a federally regulated bank is not considered a "security" under federal securities laws and therefore does not fall within their purview. The Weavers had purchased a CD from Marine Bank to secure an investment in another company which later failed. They sued the bank for failing to disclose risks associated with this investment, alleging violations of federal securities law. However, the court held that CDs are protected by banking laws and regulations which provide safeguards similar to those offered by securities laws - such as FDIC insurance and regular audits - making additional protection unnecessary.

In the dissenting opinion for Marine Bank v. Weaver, Justice William Brennan disagreed with the majority's ruling that a Certificate of Deposit (CD) issued by a federally regulated bank is not considered a security under federal securities laws. He argued that this interpretation was too narrow and inconsistent with previous court decisions which had broadly defined what constitutes as securities to protect investors from fraud and manipulation. He also pointed out that CDs are often sold in public markets where they can be bought by unsophisticated investors who need protection from fraudulent practices. Therefore, he believed these should fall within the purview of federal securities laws.