POSCO is a South Korean steel manufacturer headquartered in Pohang, South Korea. It had an output of 42,000,000 metric tons of crude steel in 2015, making it the world's sixth-largest steelmaker by this measure. In 2010, it was the world's largest steel manufacturing company by market value. Also, in 2024, it was named as the world's 233rd-largest corporation by the Fortune Global 500. POSCO currently operates two integrated steel mills in South Korea, in Pohang and Gwangyang. POSCO previously operated a joint venture with U.S. Steel, USS-POSCO Industries, in Pittsburg, California, United States, but U.S. Steel acquired full ownership of the facility in February 2020. Wikipedia