Changes

== Antitrust law in the U.S ==

== Antitrust law in the U.S ==

In the United States, monopoly policy has been built on the Sherman Antitrust Act of 1890. This prohibited contracts or conspiracies to restrain trade or, in the words of a later act, to monopolize commerce. In the early 20th century this law was used to reduce the economic power wielded by so-called "robber barons", such as JP Morgan and John D. Rockefeller, who dominated much of American industry through huge trusts that controlled companies' voting shares. Du Pont chemicals, the railroad companies and Rockefeller's Standard Oil, among others, were broken up. In the 1970s the Sherman Act was turned (ultimately without success) against IBM, and in 1982 it secured the break-up of AT&T's nationwide telecoms monopoly.

In the United States, monopoly policy has been built on the [[Sherman Antitrust Act of 1890]]. This prohibited contracts or conspiracies to restrain trade or, in the words of a later act, to monopolize commerce. In the early 20th century this law was used to reduce the economic power wielded by so-called "robber barons", such as JP Morgan and John D. Rockefeller, who dominated much of American industry through huge trusts that controlled companies' voting shares. Du Pont chemicals, the railroad companies and Rockefeller's Standard Oil, among others, were broken up. In the 1970s the Sherman Act was turned (ultimately without success) against IBM, and in 1982 it secured the break-up of AT&T's nationwide telecoms monopoly.

In the 1980s a more laissez-faire approach was adopted, underpinned by economic theories from the Chicago school. These theories said that the only justification for antitrust intervention should be that a lack of competition harmed consumers, and not that a firm had become, in some ill-defined sense, too big. Some monopolistic activities previously targeted by antitrust authorities, such as predatory pricing and exclusive marketing agreements, were much less harmful to consumers than had been thought in the past. They also criticized the traditional method of identifying a monopoly, which was based on looking at what percentage of a market was served by the biggest firm or firms, using a measure known as the herfindahl-hirschman index. Instead, they argued that even a market dominated by one firm need not be a matter of antitrust concern, provided it was a contestable market.

In the 1980s a more laissez-faire approach was adopted, underpinned by economic theories from the Chicago school. These theories said that the only justification for antitrust intervention should be that a lack of competition harmed consumers, and not that a firm had become, in some ill-defined sense, too big. Some monopolistic activities previously targeted by antitrust authorities, such as predatory pricing and exclusive marketing agreements, were much less harmful to consumers than had been thought in the past. They also criticized the traditional method of identifying a monopoly, which was based on looking at what percentage of a market was served by the biggest firm or firms, using a measure known as the herfindahl-hirschman index. Instead, they argued that even a market dominated by one firm need not be a matter of antitrust concern, provided it was a contestable market.

* Peritz, Rudolph J. R. "Three Visions of Managed Competition,  1920-1950," ''Antitrust Bulletin'', Spring 1994 39 #1 273-287.

* Peritz, Rudolph J. R. "Three Visions of Managed Competition,  1920-1950," ''Antitrust Bulletin'', Spring 1994 39 #1 273-287.

* Stelzer, Irwin M. ''Selected Antitrust Cases: Landmark Decisions in Federal Antitrust'' (1961) [http://www.questia.com/PM.qst?a=o&d=58185094 online edition]

* Stelzer, Irwin M. ''Selected Antitrust Cases: Landmark Decisions in Federal Antitrust'' (1961) [http://www.questia.com/PM.qst?a=o&d=58185094 online edition]

* Thorelli, Hans. ''The Federeal Antitrust Policy'' (1954)

* Thorelli, Hans. ''The Federal Antitrust Policy'' (1954)

===Europe===

===Europe===