During the Japanese economic bubble, Forbes listed Tsutsumi as the wealthiest person in the world during 1987–94[1][2] due to his extensive real estate investments through the Seibu Corporation, which he controlled.
Though Seiji subsequently parlayed these stores into the Credit Saison empire, perceived rivalry between the two brothers' fiefdoms provided fodder for the popular press.
[15] Despite his resignation, he continued to exert significant control over the committee by selecting future chairmen, which effectively prevented his opponents from serving in the position.
[16] Tsutsumi's total net worth has been unclear, as it is unknown how much he owned in assets: he almost always refused interviews, and did not permit Seibu spokespeople to reveal company information.
[19][20] The January 17, 2005 edition of The Wall Street Journal made an investigation on Tsutsumi and the Seibu Corporation public to English readers.
According to the paper, the Seibu corporation's headquarters were raided by police, who allegedly found evidence of several Japanese business law-breaking incidents.
[21] While multiple Seibu employees were involved in the scandal, Tsutsumi was considered the ringleader, as a result of position in the company and his authoritarian management style.
Tsutsumi pleaded guilty, and on October 27, 2005, the Tokyo District Court sentenced him to 30 months in prison, suspended for 4 years, and a fine of 5 million yen.