This article is devoted to the problem of the detection of overt or tacit collusion equilibrium in the context of the choice of the appropriate econometric method, a choice that is determined by the amount of information that the observer possesses. The author addresses this problem in two steps. First, to provide a theoretical background, he uses a collusion marker based on structural disturbances in a price process’ variance. Then, he applies a Markov switching model with switching in variance regimes.