A group of firms with a formal agreement to collude and act as a monopoly is called a:

1. Colluding firms try to capture monopoly profits without merging. 2. A group of firms that have a formal agreement to collude is called a cartel. 3. The agreement is to produce the monopoly output and sell at the monopoly price. 4. A merger would combine the firms into one rather than leaving them separate. _Source: OpenStax Principles of Microeconomics for AP(R) Courses 2e (CC BY 4.0), Ch 10 'Monopolistic Competition and Oligopoly', sections 10.1-10.2_