The story
Fujitsu Ten was created in 1972 when it was spun out by Fujitsu. It took with it the automotive and radio electronics departments. The intention was that creating a separate company would give more focus to these areas. The automotive and radio departments were themselves the result of a merger between Fujitsu Limited and Kobe Industries Corp. in 1968. In 1974, Toyota invested in the company.
In September 2016, Denso agreed with Fujitsu to purchase the stock of Fujitsu Ten. The deal was made on November 1, 2017, and its name was changed to Denso Ten. This resulted in Denso increasing its share from 10% to 51%, Fujitsu reducing from 55% to 14% and Toyota remaining at 35%.
From Wikipedia’s article on Denso Ten, shared under CC BY-SA 4.0.4