S-Oil Corporation (hangul:에쓰오일) is a petroleum and refinery company, headquartered in Seoul, Korea. It was established in 1976 by old name SsangYong Refinery (hangul:쌍용정유). It produces petroleum, petrochemical, and lubricant products, as well as polysilicon products through its investment in Hankook Silicon. The company is one of the most profitable energy companies in Korea. The company was listed as a Fortune Global 500 company in 2009. (Rank 441). In the same year, the company was also awarded as "The Downstream Business of the Year" at the Platts Global Energy Awards. S-Oil's Onsan Refinery in Ulsan boasts a capacity of 580,000 barrels per day (BPD), along with a world-class Bunker-C Cracking Center(BCC), a Xylene Center, a Para-xylene plant with the world’s highest production capacity for a single facility. Its competitors in Korea include SK Energy, GS Caltex, and Hyundai Oilbank.