First established in 1876 with 16 members including the founder, Takashi Masuda.
Subsidiary Mitsui Oil Exploration's MOEX Offshore had a 10% stake in the Deepwater Horizon well in the Gulf of Mexico through a subsidiary, and in May, 2011, MOEX agreed to pay US$1.07 billion to settle British Petroleum claims against it over the explosion and oil spill at the well.