This paper investigates the origin and propagation of balance sheet recessions. I first show that in standard models driven by TFP shocks, the balance sheet channel disappears when agents can write contracts on the aggregate state of the economy. Optimal contracts sever the link between leverage and aggregate risk sharing, eliminating the concentration of aggregate risk that drives balance sheet recessions. I then show that uncertainty shocks can help explain this concentration of aggregate risk and drive balance sheet recessions, even with contracts on aggregate shocks. The mechanism is quantitatively important, and I explore implications for financial regulation.

We characterize optimal asset management contracts in a classic portfolio‐investment setting. When the agent has access to hidden savings, his incentives to misbehave depend on his precautionary saving motive. The contract dynamically distorts the agent's access to capital to manipulate his precautionary saving motive and reduce incentives for misbehavior. We provide a sufficient condition for the validity of the first‐order approach, which holds in the optimal contract: global incentive compatibility is ensured if the agent's precautionary saving motive weakens after bad outcomes. We extend our results to incorporate market risk, hidden investment, and renegotiation.