A cartel is branch of an oligopoly. There are still a handful of large firms and many smaller firms. For instance, the diamond industry and the petroleum industries are examples are oligopolies. However, the main difference is that there is cooperation among the firms. Cooperation with output, price, marketing, distribution and future planning. Within a capitalist economy, an oligopoly would not maximize efficiency for both the consumer OR the producer. Does this make the completion much more fierce? Less?