| May 1968 | Tohmatsu Awoki & Co. established |
| May 1976 | Joined Touche Ross International (“TRI”) alliance |
| October 1986 | Merged with Sanwa & Co. (established in 1973) and changed company name to Tohmatsu Awoki & Sanwa |
| April 1988 | Merged with Marunouchi & Co. (established in 1968) |
| October 1988 | Merged with Nishikata Audit Corporation (established in 1969) and Sapporo Dai-ichi Kaikei Audit Corporation (established in 1976) |
| February 1990 | The merger of TRI with Deloitte Haskins & Sells (“DH&S”) in the U.S. led the way for the merger of Tohmatsu Awoki & Sanwa with Mita Audit Corporation (DH&S-Japan established in 1985) which resulted in a change of the company name to Tohmatsu & Co. |
| April 2001 | Merged with SAN-AI Audit Corporation (established in 1983) |
| July 2002 | Merged with Seiwa Audit Corporation (established in 1974) |
| April 2004 | Changed company name in English to Deloitte Touche Tohmatsu |
| July 2009 | Converted to a limited liability company and changed company name in English to Deloitte Touche Tohmatsu LLC |