Capital reallocation is procyclical in the data, but countercyclical in standard businesscycle models. To solve this puzzle, I build a model of endogenous partial irreversibility, with heterogeneous firms facing aggregate and idiosyncratic productivity shocks. Used investment goods are imperfect substitutes for new ones because of firm-level capital specificity. The price of used capital responds to aggregate shocks, leading to equilibrium real-option effects on investment and reallocation. The model generates procyclical capital reallocation and procyclical price of used capital, consistent with new industrylevel evidence I present, and provides a microfoundation for both micro and macro capital adjustment costs.

Capital reallocation is procyclical in the data, but countercyclical in standard businesscycle models. To solve this puzzle, I build a model of endogenous partial irreversibility, with heterogeneous firms facing aggregate and idiosyncratic productivity shocks. Used investment goods are imperfect substitutes for new ones because of firm-level capital specificity. The price of used capital responds to aggregate shocks, leading to equilibrium real-option effects on investment and reallocation. The model generates procyclical capital reallocation and procyclical price of used capital, consistent with new industrylevel evidence I present, and provides a microfoundation for both micro and macro capital adjustment costs.

We consider models where the Ramsey-optimal fiscal policy under Full Commitment (FC) is time-inconsistent and define a new notion of optimal policy, Limited-Time Commitment (LTC). Successive one-period lived governments can commit to future plans over a finite horizon. We provide a sufficient condition on the mapping from finite policy sequences to allocations, such that LTC and FC lead to the same outcomes. We then show that this condition is verified in several existing models, allowing FC Ramsey plans to be supported with a finite commitment horizon (often a single period). We relate the required degree of commitment to the economic environment: in economies without capital, the minimum degree of commitment required is given by the government debt maturity; in economies with capital and government balanced-budget constraints, the required commitment is given by the horizon over which the budget has to be balanced. Finally, we solve numerically for the LTC equilibrium of an economy where the equivalence result fails and show that a single year of commitment to capital taxes provides substantial welfare gains relative to the No-Commitment time-consistent policy.

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This article studies equilibrium dynamics in consumer durable goods markets after aggregate credit shocks. We introduce two novel features into a general-equilibrium model of durable consumption with heterogeneous households facing idiosyncratic income risk and borrowing constraints: (1) indivisible durable goods are vertically differentiated in their quality and (2) trade on secondary markets at marketclearing prices, with households endogenously choosing when to trade or scrap their durables. The model highlights a new transmission mechanism for macroeconomic shocks and successfully matches several empirical patterns that we document using data on U.S. car markets around the Great Recession. After a tightening of the borrowing limit, debt-constrained households postpone the decision to scrap and upgrade their low-quality cars, which depresses mid-quality car prices. In turn, this effect reduces wealthy households' incentives to replace their mid-quality cars with high-quality ones, thereby decreasing new-car sales. We further use our framework to evaluate targeted fiscal stimulus policies such as the Car Allowance Rebate System in 2009 ("Cash for Clunkers").