We develop a q theory of investment with endogenous leverage, payout, hedging, and risk-taking dynamics. The key frictions are costly equity issuance and incomplete markets. We show that the marginal source of external financing on an on-going basis is debt. The firm lowers its debt when making...

An equilibrium model of financial crises driven by Irving Fisher's financial amplification mechanism features a pecuniary externality, because private agents do not internalize how the price of assets used for collateral respond to collective borrowing decisions, particularly when binding...

The confluence of three trends in the U.S. residential housing market---rising home prices, declining interest rates, and near-frictionless refinancing opportunities---led to vastly increased systemic risk in the financial system. Individually, each of these trends is benign, but when they occur...