The Assa Abloy Group is a Swedish lock manufacturer, the world's largest by sales. Assa Abloy was formed in 1994 when ASSA AB was detached from Swedish security firm Securitas AB. Shortly thereafter the Finnish high-security lock manufacturer Abloy Oy (a subsidiary of the Finnish company Wärtsilä) was acquired. The company was introduced to the Stockholm stock exchange later the same year. Assa Abloy now owns Yale lock, Sargent and the high-security lock firms of Medeco in the U.S.