Altos Hornos de Mexico SAB de CV (AHMSA) is a Mexico-based company active in the steel sector. The Company specializes in the production of basic raw materials and finished products. The Company's product portfolio includes cold-rolled steel, used for door panels and windows; hot- rolled flat products such as pressure vessel steel, structural steel, pipeline and drilling pipe steel, used for machinery parts, agricultural tools, railroad tanks and bridge constructions; and structural shapes, used in the manufacturing industry. AHMSA operates several coal and iron mines. It is a subsidiary of Grupo Acerero del Norte SA de CV. The Company’s subsidiaries include Minerales Monclova SA de CV and Nacional de Acero SA de CV. On April 30, 2008, the Company’s subsidiaries, such as Minera Carbonifera Rio Escondido SA de CV, Minera del Norte SA de CV, Cerro de Mercado SA de CV were incorporated into Minerales Monclova SA de CV.