In microeconomics, management, and international political economy, vertical integration refers to an arrangement in which the supply chain of a company is integrated and owned by that company. Usually each member of the supply chain produces a different product or (market-specific) service, and the products combine to satisfy a common need. It is contrasted with horizontal integration, wherein a company produces several items that are related to one another. Vertical integration has also described management styles that bring large portions of the supply chain not only under a common ownership but also into one corporation (as in the 1920s when the Ford River Rouge Complex began making much of its own steel rather than buying it from suppliers).