In large cities real estate brokers typically charge clients no more than a 6% commission. Tinas Property Hunters, Amys Timberland Property and the Belleayre Realty are the only three real estate brokerage firms in a small city. Due to the limited amount of work available for brokers their city, the three firms have gotten together and agreed to never charge a commission below 10%. Discuss if this is acceptable under the Sherman Act.