Debt Collateralization, Capital Structure, and Maximal Leverage

We study how allowing agents to use debt as collateral affects asset prices, leverage, and interest rates in a general equilibrium, heterogeneous-agent model with collateralized financial contracts and multiple states of uncertainty. In the absence of debt collateralization, multiple contracts are traded in equilibrium, with some agents borrowing using risky debt and others borrowing with risk-free debt. When agents can use debt contracts as collateral to borrow from other agents, margin requirements decrease, asset prices increase, and the interest rate on risky debt decreases. We characterize equilibrium for N states and L levels of debt collateralization and prove that enough levels of debt collateralization creates an equilibrium featuring maximal leverage on all debt contracts. In the dynamic model, debt collateralization creates larger asset price volatility.