antitrust law

Since competition usually drives down prices for customers, the government tries to ensure that no major industry suffers from a lack of competitiveness. This almost always involves laws that preclude explicit collusion between companies regarding setting prices. It sometimes involves the government blocking companies from merging with each other or buying one another. When there are only a few number of companies in an industry, there are usually stringent laws on how much those companies can charge their customers (e.g. utilities like power and water suppliers).