A Macro-Finance Model with Sentiment

Abstract This paper incorporates diagnostic expectations into a general equilibrium macroeconomic model with a financial intermediary sector. Diagnostic expectations are a forward-looking model of extrapolative expectations that overreact to recent news. Frictions in financial intermediation produce non-linear spikes in risk premia and slumps in investment during periods of financial distress. The interaction of sentiment with financial frictions generates a short-run amplification effect followed by a long-run reversal effect, termed the feedback from behavioural frictions to financial frictions. The model features sentiment-driven financial crises characterized by low pre-crisis risk premia and neglected risk. The conflicting short-run and long-run effect of sentiment produces boom–bust investment cycles. The model also identifies a stabilizing role for diagnostic expectations. Under the baseline calibration, financial crises are less likely to occur when expectations are diagnostic than when they are rational.