Indian Oil Corporation is an Indian public-sector petroleum company. It is India�s largest commercial enterprise, ranking 116th on the Fortune Global 500 listing (2008). It began operation in 1959 as Indian Oil Company Ltd. The Indian Oil Corporation was formed in 1964, with the merger of Indian Refineries Ltd. Indian Oil and its subsidiaries account for a 47% share in the petroleum products market, 40% share in refining capacity and 67% downstream sector pipelines capacity in India. The Indian Oil Group of Companies owns and operates 10 of India's 19 refineries with a combined refining capacity of 60.2 million metric tons per year.