Historical stock prices for Jefferies Group (JEF). Jefferies Group, Inc. is a United States-based firm that operates as a securities and investment banking firm. The Company's principal operating subsidiary is Jefferies & Company, Inc. (Jefferies). The Company operates in two business segments, Capital Markets and Asset Management. Its Capital Markets segment consists of the Company's securities and commodities trading activities (including the results of its indirectly partially-owned subsidiary, Jefferies High Yield Trading, LLC), and its investment banking activities. The Capital Markets segment provides the research, sales, trading and/or origination and execution for various equity, fixed income and advisory products and services. The Asset Management segment includes asset management activities and related services.