These four essays address issues related to the incompleteness of financial markets in competitive exchange economies. The main point we try to establish is that when markets are incomplete, a wide range of economic policies have an impact on equilibrium allocations and therefore on the welfare...

The quality of information in financial asset markets is often hard to estimate. This paper analyzes information transmission in asset markets when agents treat information of unknown quality as ambiguous. We consider a market with risk-averse informed investors, risk-neutral competitive...