Transocean Ltd. is an American drilling company. It is the world's largest offshore drilling contractor based on revenue and is based in Steinhausen, Switzerland. The company has offices in 20 countries, including Canada, the United States, Norway, United Kingdom, India, Brazil, Singapore, Indonesia, and Malaysia. In 2010, Transocean was found partially responsible for the Deepwater Horizon oil spill resulting from the explosion of one of its oil rigs in the Gulf of America. The primary business of Transocean is contracts with other large companies in the oil and gas industry. In 2019, Royal Dutch Shell accounted for 26% of the company's revenues, while Equinor accounted for 21% of the company's revenues, and Chevron accounted for 17% of the company's revenues. Wikipedia