An acquisition occurs when one company purchases another, usually with the purchasing company being larger. A merger involves two companies combining to form an entirely new company. There are several types of mergers and acquisitions including horizontal, vertical, conglomerate, and triangular structures. Mergers and acquisitions are regulated globally and within countries to assess the competitive impacts and effects on shareholders. Reasons for mergers and acquisitions include achieving economies of scale, increased market share, and entering new markets, though they sometimes fail due to cultural clashes, lack of planning, or ego problems.