The Sherman Antitrust Act has to do with fairness in the marketplace. The Act prohibits price -fixing. For the real estate industry, this translates to a prohibition of commission-fixing. In other words, if commission rates were fixed at a certain percentage, the consumer would have no ability to shop for the best deal on a brokerage commission, since all commission rates are the same. Discussing or even mentioning commission rates with other brokers is strictly prohibited by the Sherman Antitrust Act.