Which of the following is NOT a main type of collusion?

Collusion generally refers to a cooperative agreement between competitors to limit competition, which can lead to various anti-competitive practices. The main types of collusion typically include collusion to raise prices, collusion to control market behavior, and collusion to divide markets among competitors.

When considering the options, collusion to raise prices involves firms working together to set higher prices than the market would dictate, which is a primary motive for collusion. Similarly, collusion to dominate market behavior reflects actions taken by companies to collectively influence their market, ensuring they operate in alignment against competitors. Dividing markets allows firms to carve out territories or customer segments to minimize direct competition, another classic form of collusion.

On the other hand, collusion to reduce production costs does not align with the traditional definitions of collusion. While firms may seek to lower production costs independently or through legitimate partnerships, this does not typically involve anti-competitive practices aimed at manipulating market conditions like the other types mentioned. Instead, such behavior may even lead to increased competition and efficiency in the market, thus falling outside the standard forms of collusion.