Which practice is considered illegal under the Sherman Antitrust Act?

Price fixing is considered illegal under the Sherman Antitrust Act because it violates the principles of free competition by allowing businesses to collaborate on setting prices, rather than letting market forces determine them. This practice undermines competition in the marketplace, which can lead to higher prices and less choice for consumers.

The Sherman Antitrust Act was established to promote fair competition by prohibiting practices that restrain trade. When companies engage in price fixing, they coordinate to keep prices artificially high, which can harm both consumers and other businesses that compete in the market. This is why price fixing is viewed as a serious violation of antitrust laws and can lead to significant penalties for those involved.

In contrast, practices like setting a standard commission, advertising together, or sharing market data can fall within acceptable parameters if they are done in compliance with antitrust laws and do not restrict competition.