Chevron Corporation (Chevron) manages its investments in subsidiaries and affiliates, and provides administrative, financial, management and technology support to the United States and International subsidiaries that engage in fully integrated petroleum operations, chemicals operations, mining operations of coal and other minerals, power generation and energy services. Exploration and production (upstream) operations consist of exploring for, developing and producing crude oil and natural gas, and also marketing natural gas. Refining, marketing and transportation (downstream) operations relate to refining crude oil into finished petroleum products; marketing crude oil and the many products derived from petroleum, and transporting crude oil, natural gas and petroleum products by pipeline, marine vessel, motor equipment and rail car. In April 2009, Reliance Industries Limited bought back Chevron Corporation's 5% stake in Reliance Petroleum Limited.