Transocean Ltd. is one of the world's largest offshore drilling contractors. The Swiss-based company rents floating mobile drill rigs, along with the equipment and personnel for operations, to oil and gas companies at an average daily rate of US$282,700 (2010). Transocean's day rates extend as high as US$650,000 for its deep-water drillships, which house dual activity derricks and can drill in ultra-deep ocean depths of . In 2010, Transocean has been implicated in the Deepwater Horizon oil spill resulting from the explosion of one of its oil rigs in the Gulf of Mexico.