From Tekkenpedia

The Mishima Zaibatsu is a company in the Tekken series. It was owned originally by Jinpachi Mishima, but the Zaibatsu was taken over by Heihachi Mishima, who has run the company for over 40 years, except for two brief interims. The companies grouped together in the syndicate include the Mishima Financial Empire, the mercenary group known as Tekken Force, and Mishima Heavy Industries. The Mishima Zaibatsu is the main sponsor of The King of Iron Fist Tournaments, the central events of the video games. In Tekken 5, Jinpachi Mishima regained control of the Mishima Zaibatsu. However, Jinpachi was defeated by Jin Kazama during The King of Iron Fist Tournament 5, and Jin gained control of the Zaibatsu.

[edit] Ownership

The constant change of ownership of the Zaibatsu is one of the Tekken series' many little quirks. To date, there are five changes of ownership known:

Several decades before the first King of Iron Fist Tournament

Jinpachi Mishima lost the Zaibatsu to his son, Heihachi Mishima

Tekken

Heihachi lost the Zaibatsu to his son, Kazuya Mishima

Tekken 2

Kazuya lost the Zaibatsu to Heihachi

Tekken 3

Heihachi remains as the owner

Tekken 4

Heihachi remains as the owner

Between Tekken 4 and Tekken 5/Tekken 5: Dark Resurrection

Jinpachi reclaims the Zaibatsu after Heihachi is assumed dead

Tekken 5/Tekken 5: Dark Resurrection

Jinpachi lost the Zaibatsu to Jin Kazama