Antitrust policy is a set of laws and regulations that are designed to promote competition and prevent monopolies. This is done by breaking up monopolies, preventing mergers that would create monopolies, and regulating the behavior of businesses to prevent them from engaging in anti-competitive practices.

The four main types of market structure are perfect competition, monopoly, oligopoly, and monopolistic competition. Perfect competition is a market structure in which there are many buyers and sellers, and each firm produces a homogeneous product. Monopoly is a market structure in which there is only one seller of a product. Oligopoly is a market structure in which there are a few large sellers of a product. Monopolistic competition is a market structure in which there are many sellers of a differentiated product.

The Herfindahl-Hirschman Index (HHI) is a measure of market concentration. It is calculated by squaring the market share of each firm in a market and then summing the results. The HHI can range from 0 to 10,000. A higher HHI indicates a more concentrated market.

The Sherman Antitrust Act is the first federal antitrust law in the United States. It was enacted in 1890 and prohibits monopolies, cartels, and other anti-competitive practices.

The Clayton Act is the law that regulates mergers and acquisitions. It was enacted in 1914 and prohibits mergers and acquisitions that would substantially lessen competition.

The Federal Trade Commission (FTC) is the federal agency that enforces antitrust laws. It was created in 1914 and is responsible for investigating and prosecuting violations of antitrust laws.

A horizontal merger is a merger between two firms in the same market. This type of merger can lead to a decrease in competition and higher prices for consumers. A vertical merger is a merger between two firms in different markets. This type of merger can lead to increased efficiency and lower prices for consumers.

The Robinson-Patman Act is a law that prevents price discrimination. It was enacted in 1936 and prohibits sellers from charging different prices to different buyers for the same product.

The Hart-Scott-Rodino Antitrust Improvements Act is a law that requires firms to notify the government before they merge. It also gives the government the power to block mergers that would substantially lessen competition. The law was enacted in 1976 and created a premerger notification program.

The National Cooperative Research and Production Act is a law that allows firms to form joint ventures to conduct research and development, produce goods and services, and market their products. The law was enacted in 1984 and provides antitrust immunity for joint ventures that meet certain criteria.

The Export Trading Company Act is a law that promotes exports from the United States, provides antitrust immunity for export trading companies, and creates a program to help small businesses export their products. The law was enacted in 1982.

The Foreign Trade Antitrust Improvements Act is a law that clarifies the application of antitrust laws to foreign commerce, provides antitrust immunity for certain export cartels, and creates a safe harbor for joint ventures that are formed to export goods and services. The law was enacted in 1982.

The North American Free Trade Agreement (NAFTA) is a law that creates a free trade area between the United States, Canada, and Mexico. The agreement reduces tariffs and other trade barriers between the three countries and promotes economic growth and job creation.

The World Trade Organization (WTO) is an international organization that regulates international trade. The WTO promotes free trade, resolves trade disputes, and provides a forum for negotiations on trade agreements.

The General Agreement on Tariffs and Trade (GATT) is an international agreement that reduces tariffs and other trade barriers. The GATT promotes free trade, resolves trade disputes, and provides a forum for negotiations on trade agreements.