Major Public Companies

• Business: Investing: Stocks and Bonds: Exchanges 

• Occidental Petroleum Corporation  - Los Angeles, California based oil and gas exploration and production company. Also produces basic chemicals, plastics, and petrochemicals.
• Office Depot  - Provider of office supplies, furniture, and other related products. Site provides information on corporate affairs, shopping tools, and a store locator.
• OfficeMax  - Supplies office supplies and furniture as well as computers and other consumer electronics.
• OGE Energy Corporation  - Natural gas pipeline business and the parent company of the Oklahoma Gas and Electric Company (OG&E).
• Oil States International, Inc.  - Oil equipment and services company provides specialty products to the oil and gas drilling production industry.
• Old Republic International  - Insurance holding company engaged in general, commercial property and liability, mortgage guarantee, title, and workers' compensation insurance.
• Olin Corporation  - Clayton, Missouri based maker of copper and copper alloy sheets, strips, clad metal, foil, and stainless steel strips.
• Omnicare  - Covington, Kentucky based company provides services in skilled nursing, assisted living, and other healthcare facilities.
• Omnicom Group  - Corporate media services conglomerate that operates advertising, marketing, and public relations segments.
• Oneok  - Diversified oil and gas company based in Tulsa, Oklahoma - a rural natural gas distributor.
• Oracle Corporation  - Suppliers of software for business information management.
• O'Reilly Auto Parts  - Information on products and services, promotions, store locations, corporate governance, and investor relations.
• Oshkosh  - Truck corporation designs and builds specialty trucks and truck bodies.
• OSI Restaurant Partners, Inc.  - Operates casual-dining spots and steakhousesin over 1,400 locations in the United States and abroad.
• Owens & Minor  - Supply-chain solutions company and distributor of name-brand medical and surgical supplies.
• Owens Corning  - Company specializing in building materials such as insulation, roofing shingles, basement finishing, vinyl sliding, and fiberglass composites.
• Owens-Illinois, Inc.  - Glass container manufacturer with a market reach in Europe, North America, Asia Pacific and Latin America.