  In this paper we study the evolution of asset price bubbles driven by
contagion effects spreading among investors via a random matching mechanism in
a discrete-time version of the liquidity based model of [25]. To this scope, we
extend the Markov conditionally independent dynamic directed random matching of
[13] to a stochastic setting to include stochastic exogenous factors in the
model. We derive conditions guaranteeing that the financial market model is
arbitrage-free and present some numerical simulation illustrating our approach.
