Anti-competitive agreements, also known as collusion, are agreements between competitors to fix prices, limit production, or allocate markets, which restrict competition. The purpose of these agreements is to increase the profits of the companies involved, often to the detriment of consumers.

In the United States, anti-competitive agreements are illegal under federal antitrust laws, such as the Sherman Act and the Clayton Act. The Department of Justice and the Federal Trade Commission are responsible for enforcing these laws, and have the power to investigate and punish companies that engage in such practices.

One of the most famous cases of anti-competitive agreements is United States v. Microsoft. In this case, Microsoft was accused of engaging in anti-competitive practices by bundling its web browser, Internet Explorer, with its Windows operating system, and by entering into agreements with computer manufacturers to prevent them from installing competing web browsers. The case was settled in 2001, and Microsoft was required to allow computer manufacturers to install non-Microsoft web browsers on their systems.

Another recent case involved the pharmaceutical industry. In 2019, the Department of Justice filed a lawsuit against Teva Pharmaceuticals and other generic drug manufacturers, alleging that they had engaged in a conspiracy to fix prices and allocate customers for generic drugs. The case is ongoing, and if the allegations are proven, the companies could be fined millions of dollars and forced to pay restitution to consumers who were affected by the price-fixing.

In addition to federal antitrust laws, many states have their own laws that prohibit anti-competitive agreements. For example, California`s Cartwright Act prohibits contracts or agreements that restrain trade or competition. Other states have similar laws that are designed to promote competition and protect consumers.

In conclusion, anti-competitive agreements are illegal under federal and state antitrust laws, and companies that engage in such practices can face significant fines and legal consequences. Consumers are the biggest victims of these agreements, as they are often forced to pay higher prices for goods and services. It is essential for companies to comply with antitrust laws and promote fair competition in the marketplace.