| Ok Champion Corporation ( Hammond, IN ) | Okabe Co., Ltd. ( Vernon Hills, IL ) | Okahata; Yoshio( Kanagawa ) |
| OK Industries Inc. ( Yonkers, NY ) | Okabe Company, Inc. ( Vernon Hills, IL ) | Okahata; Yoshio( Kawasaki ) |
| OK International Inc. ( Yonkers, NY ) | Okabe Corporation ( Vernon Hills, IL ) | Okalahoma Medical Research Foundation ( Oklahoma City, OK ) |
| OK Orenstein und Koppel AG( Berlin ) | Okabe Giken Co., Ltd.( Shinagawa-ku ) | OKAMI Yoshiro ( Chiba, JP ) |
| OK Plast ( Horsens, DE ) | Okabe Mica Co., Ltd. ( Fukuoka, JP ) | OKAMOTO CHEMICAL INDUSTRY CO. LTD. |
| Ok Shin Jin( Seoul ) | Okabe; Shuji( Osaka ) | Okamoto Chemical Industry Co., Ltd. |
| OK Technologies LLC | Okada Aiyon( Osaka ) | Okamoto Chemical Industry Co., Ltd. ( Saitama, JP ) |
| OK Technologies, LLC | Okada Electric Co, Ltd. ( Nagoya, JP ) | Okamoto Chemical Industry Co., Ltd.( Saitama-ken ) |
| OK Technologies, LLC ( Greensboro, NC ) | Okada Kazuhiro | Okamoto Chemical Industry Co., Ltd.( Warabi ) |
| OK YEO CHONG ( Seoul, KR ) | Okada Masuo | OKAMOTO CHEMICAL INDUSTRY CO.,LTD. |
| OK-1 Manufacturing Company ( Altus, OK ) | Okada Metal Industries Co., Ltd.( Hyogo ) | Okamoto Co., Ltd. |
| OK-1 Manufacturing Company, Inc. ( Altus, OK ) | Okada Shigyo Co., Ltd.( Osaka ) | Okamoto Co., Ltd.( Gifu ) |
| Oka Tool Company ( Cincinnati, OH ) | Okada; Hidechika ( both of, JP ) | OKAMOTO CORPORATION |
| Okabashi Brands, Inc. ( Buford, GA ) | Okada; Masao | OKAMOTO CORPORATION ( KITAKATSURAGI-GUN, NARA-KEN, JP ) |
| Okabe Co., Inc. | Okada; Masuo | Okamoto Corporation( Nara ) |
| Okabe Co., Ltd. ( Fukuoka, JP ) | Okahata Yoshio | Okamoto Industries ( Tokyo, JP ) |
| Okabe Co., Ltd. ( Tokyo, JP ) | Okahata Yoshio( Kanagawa ) | |