Definition of Security The Farmer's Cooperative of Arkansas and Oklahoma (Co-Op) was an agricultural cooperative that had approximately 23,000 members. To raise money to support its general business operations, Co-Op sold to investors promissory notes that were payable upon demand. Co-Op offered the notes to both members and non-members, advertised the notes as an "investment program," and offered an interest rate higher than that available on savings accounts at financial institutions. More than 1,600 people purchased the notes, worth a total of $10 million. Subsequently, Co-Op filed for bankruptcy. A class of holders of the notes filed suit against Ernst & Young, a national firm of certified public accountants that had audited Co-Op's financial statements, alleging that Ernst & Young had violated Section 10(b) of the Securities Exchange Act of 1934. Are the notes issued by Co-Op "securities"? Reeves v. Ernst & Young, 494 U.S. 56, 110 S.Ct. 945, 108 L.Ed.2d 47, Web 1990 U.S. Lexis 1051 (Supreme Court of the United States)