[5] In the United States Mitsui's subsidiary is MOEX USA Corp[6] and is headquartered in 9 Greenway Plaza in Houston.
In September 2007 it established subsidiary MOEX Offshore 2007 LLC which entered into a partnership with BP for drilling in the Gulf of Mexico.
In May, 2011, MOEX Offshore, having had a 10% stake in the Deepwater Horizon through a subsidiary, agreed to pay US$1.07 billion to settle BP claims against it over the accident.
Some analysts had thought BP would realize a larger settlement from MOEX but there was also relief to have a first step toward resolving the multiple claims.
[8] In February, 2010, through subsidiary Mitsui E&P USA LLC ("MEPUSA") it acquired 32.5% of Anadarko Petroleum's interest in the Marcellus Shale gas project in Pennsylvania (thereby acquiring 15.5% interest in the entire project lease and approximately 100,000 acres (40,469 ha) of land).