merger, in corporate business, fusion of two or more corporations by the transfer of all property to a single corporation. The remaining corporation continues in existence, having absorbed the other(s). Mergers may be of various types: A vertical merger integrates different types of businesses that may share a supplier-customer relationship; a horizontal merger brings together related businesses; an extensional merger. joins two similar businesses to enter a new market; and a hostile takeover occurs when a stronger business absorbs another against its will. The methods of effecting mergers vary. Often the corporation that continues to function makes an outright purchase of the property and stock of the others; exchange of bonds, options, and other agreements are also employed by the corporations involved.

Mergers may be effected to increase profits and reduce losses through the reduction of competition, to diversify production, to protect against the liabilities of concentration in a single area, or to revive or rejuvenate failing businesses by the infusion of new management and personnel. Mergers for monopolistic purposes were among the unfair practices that the Sherman Antitrust Act (1890) and, more especially, the Clayton Antitrust Act (1914) attempted to correct. The international nature of many modern corporations now also subjects mergers to antitrust scrutiny overseas, particularly in the European Union.

The end of the 20th cent. witnessed a great increase in mergers; in the United States alone, 60,375 mergers involving a total of over $4.5 trillion occurred between 1980 and 1996. Among the largest recent U.S. mergers are those between America Online and Time Warner (2000; $165 billion, but worth significantly less after the bubble in Internet-related stocks collapsed), Exxon and Mobil (1999; $81 billion); Citicorp and Travelers Corp. (1998; $72.6 billion), AT&T and Bell South (2006; $67 billion), SBC Communications and Ameritech (1998; $60.1 billion), and AT&T and TCI (1999; $48 billion).

See also conglomerate.

Combination of two or more independent business corporations into a single enterprise, usually involving the absorption of one or more firms by a dominant firm. The dominant firm may purchase the other firm's assets with cash or securities, purchase the other firm's stock, or issue its own stock to the other firm's stockholders in exchange for their shares in the acquired firm (thus acquiring the other company's assets and liabilities). In horizontal mergers, both firms produce the same commodity or service for the same market. In vertical mergers, a firm acquires either a supplier or a customer. If the merged business is not related to that of the acquiring firm, the new corporation is called a conglomerate. The reasons for mergers are various: the acquiring firm may seek to eliminate a competitor, to increase its efficiency, to diversify its products, services, and markets, or to reduce its taxes.

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