The stability of national and, increasingly more often, the global economy relies on well-functioning financial markets. Households' consumption and saving decisions, firms' investment choices, and governments' financing strategies critically depend on the stability of financial markets. These markets, however, are composed of individuals and institutions that may have different objectives, information sets, and beliefs, making them a very complex object that we do not fully comprehend. Motivated by this, my dissertation focuses on understanding how informational asymmetries and belief heterogeneity impact financial markets, and therefore, the macro economy. More specifically, this dissertation explores the sources of informational asymmet...