| 1967 | Copper Foil Plant set up in Ageo, Saitama, Japan |
| 1968 | Commercial business started in Ageo |
| 1976 | Oak-Mitsui Inc founded in N.Y. USA |
| 1980 | Taiwan Copper Foil founded in Nanto, ROC |
| 1991 | Mitsui Copper Foil (Malaysia) founded in Selangor Darul Ehsan, Malaysia |
| 1998 | Mitsui Copper Foil (Hong Kong), sales base founded In Hong Kong |
| 1999 | Mitsui Copper Foil (Suzhou), slitting base founded In Suzhou, China |
| 2003 | Oak-Mitsui Technologies LLC, R&D company, founded in N.Y. USA |
