Ricerc@Sapienza

Financial crises often originate in debt markets, where collateral constraints and opacity of asset values generate intrinsic instability. In such ambiguous contexts endogenous beliefs formation plays a crucial role in explaining asset price and leverage cycles. We introduce state-contingent ambiguity attitudes embedding ambiguity aversion and seeking, which endogenously induces pessimism (left-skewed beliefs) in recessions and optimism (rightskewed beliefs) in booms, in a model where borrowers face occasionally binding collateral constraints. We use GMM estimation with latent value functions to estimate the ambiguity attitudes process. By simulating a crisis scenario in our model we show that optimism in booms is responsible for higher asset price and leverage growth and pessimism in recessions is responsible for sharper de-leveraging and asset price bursts. Analytically and numerically (using global methods) we show that our state-contingent ambiguity attitudes coupled with the collateral constraints can explain relevant asset price and debt cycle facts around the unfolding of a financial crisis.