Politics and Business magazines
- NYNEX Corporation
- O.C. Tanner Co.
- Oak Harbor Freight Lines, Inc.
- Oak Industries Inc.
- Oak Technology, Inc.
- Oakhurst Dairy
- Oaktree Capital Management, LLC
- Oakwood Homes Corporation
- OAO Gazprom
- OAO LUKOIL
- OAO NK YUKOS
- OAO Siberian Oil Company (Sibneft)
- OAO Surgutneftegaz
- OAO Tatneft
- Obayashi Corporation
- Obie Media Corporation
- Obrascon Huarte Lain S.A.
- Observer AB
- Océ N.V.
- Ocean Beauty Seafoods, Inc.