| Month/Year | History | 
|---|---|
| July 1969 | Founded as ELCO Co., Ltd. (Capital 2.5 million yen) ELCO stood for "Electronics" and "Control" – our main business being the use of electronics to control devices.  | 
					
| February 1970 | Opened Tokyo Sales Office (became a branch in February 1971) | 
| July 1973 | Built two-story steel-framed Head Office (total floor area 607 m2) in Kami-Akae Machi, Toyama City, Toyama Prefecture (area 3,487 m2) 
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| August 1977 | Opened Osaka Sales Office (became a branch in November 1986) | 
| April 1978 | Introduced QC Circle activities Began with 16 circles.  | 
					
| June 1978 | Began to specialize in power supply business. | 
| July 1980 | Acquired 5,502 m2 of land next door to Head Office, and began operations at three-story, steel-framed 2,723 m2 plant.
							 
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| May 1982 | Introduced TQC (Total Quality Control) | 
| June 1983 | Opened Nagoya Sales Office (became a branch in May 1992) Introduced Policy Management (definition of Long-term Policy and Annual Policy)  | 
					
| July 1985 | Opened Tama Sales Office | 
| March 1988 | Introduced Toyota Manufacturing Method | 
| March 1989 | Completed Tateyama Factory in Tateyama Machi, Toyama Prefecture
							 
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| May 1990 | Established U.S. ELCO., INC. (currently COSEL U.S.A., INC.) in San Jose, California, targeting Silicon Valley, where high-tech industry and venture companies are present in high concentrations. | 
| September 1990 | Opened Kyoto Sales Office | 
| April 1992 | Company name changed from ELCO Co., Ltd. to COSEL Co., Ltd.
							
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| June 1993 | Accredited under International Standard ISO 9001, relating to quality control and quality assurance (the first accreditation in Toyama Prefecture). | 
| December 1994 | Shares in the Company registered. Additional financing brought capital to 2.055 billion yen.  | 
					
| May 1996 | Introduced TMP. | 
| May 1997 | Extension offices in Saitama and Nagano changed to Sales Offices. | 
| July 1997 | Established COSEL EUROPE GmbH, a sales subsidiary in Germany. | 
| May 1998 | Established COSEL ASIA LTD., a sales subsidiary in Hong Kong. | 
| January 1999 | Shares listed on the Tokyo Stock Exchange and Nagoya Stock Exchange Market Division 2. | 
| November 1999 | Won TPM Excellence 1st Category. | 
| December 1999 | Acquired accreditation under International Standard ISO 14001, relating to environmental activities. | 
| May 2000 | Shares listed on the Tokyo Stock Exchange and Nagoya Stock Exchange Market Division 1. | 
| May 2002 | Head Office extended to a four-story, steel-framed building (total area 3,842.36 m2).
 			 
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| November 2002 | Established COSEL Shanghai Electronics Co., Ltd., a sales subsidiary in Shanghai, China. | 
| May 2004 | Branches and Extension offices closed, and all sales locations unified into "Sales Offices." | 
| December 2004 | Opened Hamamatsu Sales Office. | 
| December 2004 | Group-wide Quality Control (GWQC) activities begin, to include partner companies. | 
| March 2005 | Began noise filter business. | 
| December 2005 | Won the QC Circle Ishikawa Kaoru Award for the first time. | 
| February 2006 | Completed compliance with RoHS instructions. | 
| October 2006 | Won the QC Circle Managers Award. | 
| May 2007 | Tateyama Factory extended to a two-story, steel-framed building (total area 5,259.68 m2).
							 
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| February 2008 | Won the Gold Award at the JHS All-Japan QC Circle Championships. | 
| November 2011 | Established SHANGHAI COSEL INTERNATIONAL TRADING CO., LTD., an export subsidiary in Shanghai, China. | 
| December 2011 | Established WUXI COSEL ELECTRONICS CO., LTD., a manufacturing subsidiary in Jiangsu Province, China. | 
| June 2013 | Kyoto and Kobe Sales Offices merged with Osaka Sales Office. | 
| November 2013 | Tachikawa and Atsugi Sales Offices merged with Kawasaki Sales Office. | 
| December 2013 | Kawasaki Sales Office changed name to Metropolitan Area Sales Office. Hamamatsu Sales Office moved and changed name to Shizuoka Sales Office. | 
| August 2015 | Completed incorporation of Vietnam Plant. Cosel Vietnam Co., Ltd., a transformer-manufacturing subsidiary. | 
| July 2018 | Acquired POWERBOX International AB. | 
| August 2018 | Built R&D Center (five-story steel-framed, total floor area 8,205.67㎡) in KamiAkae Machi, Toyama City. | 
| October 2018 | Began operations at R&D Center. | 
| April 2022 | Shares transferred from first section to Prime Market of the Tokyo Stock Exchange due to reorganization of TSE market categories. | 
| June 2022 | Opened Kyoto Sales Office. | 
| August 2022 | Transitioned from a company with a board of auditors to one with an audit and supervisory committee. | 
| April 2024 | Signed Capital and Business Alliance agreement with LITE-ON TECHNOLOGY CORPORATION. | 
| July 2024 | Capital increased to 6.04B JPY by additional financing though Capital and Business Alliance with LITE-ON TECHNOLOGY CORPORATION. | 






