| OM CORPORATION | OM Technology AB ( Stockholm, SE ) | Omat Ltd.( Jerusalem ) |
| Om Corporation( Okayama ) | OM2P, Inc. ( Manhattan, KS ) | Omata Manufacturing Co., Ltd.( Yamanashi ) |
| OM Energy Ltd.( London ) | OMA Mfg. Co., Ltd.( Tokyo ) | O-Matic Corp. ( Claremont, CA ) |
| OM Group ( Cleveland, OH ) | Omaco Enterprises, Inc. ( Phoenix, AZ ) | Omation Corporation ( Mountain View, CA ) |
| OM Group, Inc. ( Cleveland, OH ) | Omaha Airport Authority ( Omaha, NE ) | Omation Corporation ( Palo Alto, CA ) |
| OM Group, Inc. ( Mooney Chemicals, Inc. ) | Omaha S.r.l. | OMAV S.p.A. ( Rodengo Saiano, IT ) |
| OM Industrial Co., Ltd. ( Oakayama, JP ) | Omaha Standard, Inc. ( Omaha, NE ) | OMAX Corporation |
| Om Industrial Co., Ltd. ( Okayama, JP ) | Omala Inc. ( Cheektowaga, NY ) | Omax Corporation ( Kent, WA ) |
| O-M LTD. | O'MALLEY | OMB S.R.L. ( Stenico, IT ) |
| O-M Ltd.( Osaka ) | Oman Perfumery LLC | OMBA S.r.l.( Melzo ) |
| O-M Ltd. ( Osaka, JP ) | O''Mara Incorporated ( Wayne, PA ) | OMBEK LTD. |
| OM NOVA Solutions Inc. ( Fairlawn, OH ) | Omark Industries, Inc. | OMBU Comercial Distribuidora, S.A.( Barcelona ) |
| OM PHARMA | Omark Industries, Inc. ( Portland, OR ) | Ombu Comercial Distribuidora, S.A.( Vilassar De Mar ) |
| Om Pharma( Meyrin ) | Omasa S.r.l. ( both of, IT ) | OMCI S.p.A. Officine Metalmeccaniche Construzioni Industriali ( Modena, IT ) |
| OM PHARMA ( Meyrin 2, CH ) | O-Mass AS | Omco USA, Inc. ( Milwaukee, WI ) |
| OM SURGICAL (UK) LIMITED ( London, GB ) | O-Mass AS( Oslo ) | Omcon, Inc. ( Stafford, TX ) |
| OM Technology AB | O-Mass AS ( Oslo, NO ) | |