Chennai Petroleum Corporation Limited, formerly known as Madras Refineries Limited, is a subsidiary of Indian Oil Corporation Limited which is under the ownership of Ministry of Petroleum and Natural Gas of the Government of India. It is headquartered in Chennai, India. It was formed as a joint venture in 1965 between the Government of India, Amoco and National Iranian Oil Company, having a shareholding in the ratio 74%: 13%: 13% respectively. From the grassroots stage CPCL Refinery was set up with an installed capacity of 2.5 million tonnes per year in a record time of 27 months at a cost of ₹430 million without any time or cost overrun. In 1985, Amoco disinvested in favour of GOI and the shareholding percentage of GOI and NIOC stood revised at 62% and 15.38% respectively. Later GOI disinvested 16.92% of the paid up capital in favor of Unit Trust of India, mutual funds, insurance companies and banks on 19 May 1992, thereby reducing its holding to 67.7%. The public issue of CPCL shares at a premium of ₹ 70 in 1994 was oversubscribed to an extent of 27 times and added a large shareholder base of over 90000. Wikipedia