Seiko Group (セイコー・グループ, Seikō Gurūpu) is a Japanese corporate group consisting of three core companies Seiko Group Corp. (Seiko), Seiko Instruments Inc. (SII) and Seiko Epson Corp (Epson). The three companies are linked by a common thread of timepiece technology. Epson has established its own brand image and rarely uses 'Seiko'. On January 26, 2009, Seiko Holdings and Seiko Instruments announced that the two companies will be merged on October 1, 2009, through a share swap. Seiko Instruments became a wholly-owned subsidiary of Seiko Holdings on October 1, 2009. On May 10, 2022, Seiko Holdings Corporation announced that it would rename Seiko Group Corporation as of October 1, 2022.
Seiko Watch Corp., a subsidiary of Seiko Holdings Corp., markets SEIKO watches while Seiko Instruments Inc. and Seiko Epson Corp. manufacture their movements.
Time Module (TMI), a member of the Seiko Group, was established in 1987 with funding from Seiko Watch Company, Seiko Instruments Inc., and Seiko Epson Corp. to manufacture watch movements.