Mitsui O.S.K. Lines
was a government-owned corporation in Japan that existed from 2003 to 2007, offering postal and package delivery services, banking services, and life insurance. It was the nation's largest employer, with over 400,000 employees, and ran 24,700 post offices throughout Japan. One third of all Japanese government employees worked for Japan Post. As of 2005, the President of the company was Masaharu Ikuta, formerly Chairman of Mitsui O.S.K. Lines Ltd.