Financial markets tend to be considered as competitive: they are global, with many operators and financial securities are close substitutes. Collusion and/or dominant positions that may alter their functioning are seldom mentioned: they are however relevant as documented in this article.
CHARLETY-LEPERS, P. (1999). Peut-on concevoir des abus de position dominante et ententes dans le système boursier ? Les Petites Affiches, pp. 40-43.