Before revision:  We prove the existence and uniqueness of the Stackelberg-Nash equilibrium for a reasonable set of model parameters. We also characterize it as the solution of an abstract vector forward-backward stochastic differential equation system .
After revision:  We prove the existence and uniqueness of a Nash equilibrium in both frameworks, alongside a characterization, under suitable weak interaction assumptions. We conclude the paper by presenting an extension of the basic model to a hierarchical market, for which we establish the existence, uniqueness, and characterization of a Stackelberg-Nash equilibrium .