Transocean Ltd. is the world's largest offshore drilling contractor and is based in Vernier, Switzerland. The company has offices in 20 countries, including Switzerland, Canada, United States, Norway, Scotland, India, Brazil, Singapore, Indonesia and Malaysia.In 2010, Transocean was implicated in the Deepwater Horizon oil spill resulting from the explosion of one of its oil rigs in the Gulf of Mexico.
In 2015, Chevron Corporation accounted for 14% of the company's revenues and Royal Dutch Shell accounted for 10% of the company's revenues.