Option Exercise with Temptation

This paper analyzes an agent¡¯s option exercise decision under uncertainty. The agent decides whether and when to do an irreversible activity. He is tempted by immediate gratification and suffers from self-control problems. This paper adopts the Gul and Pensendorfer self- control utility model. Unlike the time inconsistent hyperbolic discounting model, it provides an explanation of procrastination and preproperation based on time consistency. When applied to the investment and exit problems, it is shown that (i) if the project value is immediate, an investor may invest in negative NPV projects; (ii) if the production cost is immediate, a firm may exit even if it makes positive net profits; and (iii) if both rewards and costs are immediate, an agent may simply follow the myopic rule which compares only the current period benefit and cost.self-control, temptation, procrastination, preproperation, option value

Competitive Equilibria of Economies with a Continuum of Consumers and Aggregate Shocks

This paper studies competitive equilibria of a production economy with aggregate productivity shocks. There is a continuum of consumers who face borrowing constraints and individual labor endowment shocks. The dynamic economy is described in terms of sequences of aggregate distributions. The existence of sequential competitive equilibria is proven and a recursive characterization is established. In particular, it is shown that for any sequential competitive equilibrium, there exists a payoff equivalent sequential competitive equilibrium that is generated by a suitably defined recursive equilibrium with state variables including continuation value.competitive equilibrium, recursive equilibrium, aggregate distribution, heterogeneity, incomplete markets

Competitive Equilibria of Economies with a Continuum of Consumers and Aggregate Shocks

This paper studies competitive equilibria of a production economy with aggregate productivity shocks and with a continuum of consumers subject to borrowing constraints and individual labor endowment shocks. The dynamic economy is described in terms of sequences of aggregate distributions. The existence of competitive equilibrium is proven and a recursive characterization is established. In particular, it is shown that for any competitive equilibrium, there is a first period payoff equivalent competitive equilibrium that is generated by a recursive equilibrium with the state space including expected discounted utilities.

Risk, uncertainty and option exercise

Many economic decisions can be described as an option exercise or optimal stopping problem under uncertainty. Motivated by experimental evidence such as the Ellsberg Paradox, we follow Knight (1921) and distinguish risk from uncertainty. To afford this distinction, we adopt the multiple-priors utility model. We show that the impact of ambiguity on the option exercise decision depends on the relative degrees of ambiguity about continuation payoffs and termination payoffs. Consequently, ambiguity may accelerate or delay option exercise. We apply our results to firm investment and exit problems, and show that the myopic NPV rule can be optimal for an agent having an extremely high degree of ambiguity aversion.

Woodford's approach to robust policy analysis in a linear-quadratic framework

This paper extends Woodford's approach to the robustly optimal monetary policy to a general linear quadratic framework. We provide algorithms to solve for a time-invariant linear robustly optimal policy in a timeless perspective and for a time-invariant linear Markov perfect equilibrium under discretion. We apply our methods to a New Keynesian model of monetary policy with persistent cost-push shocks and inflation persistence. We find that the robustly optimal commitment inflation is less responsive to a cost-push shock when the shock is more persistent and that the robustly optimal discretionary policy is more responsive to lagged inflation when inflation is more persistent.Accepted manuscrip

Asset bubbles and credit constraints

We provide a theory of rational stock price bubbles in production economies with infinitely lived agents. Firms meet stochastic investment opportunities and face endogenous credit constraints. They are not fully committed to repaying debt. Credit constraints are derived from incentive constraints in optimal contracts which ensure default never occurs in equilibrium. Stock price bubbles can emerge through a positive feedback loop mechanism and cannot be ruled out by transversality conditions. These bubbles command a liquidity premium and raise investment by raising the debt limit. Their collapse leads to a recession and a stock market crash.Published versio

Investment, Consumption, and Hedging under Incomplete Markets

Entrepreneurs often face undiversifiable idiosyncratic risks from their business investments. We extend the standard real options approach to an incomplete markets environment and analyze their joint decisions of business investments, consumption/savings, and portfolio selection. For a lump-sum investment payoff and an agent with a su¡Àciently strong precautionary savings motive, an increase in volatility can accelerate investment, contrary to the standard real options analysis. When the agent can trade the market portfolio to partially hedge against investment risk, the systematic volatility is compensated via the standard CAPM argument, and the idiosyncratic volatility generates a private equity premium. Finally, when the investment payoff is a series of flows, the agent's idiosyncratic risk exposure alters both the implied option value and the implied project value, causing a reversal of the results in the lump-sum payoff case.real options, idiosyncratic risk, hedging, risk aversion, precautionary savings, incomplete markets

Investment, Hedging, and Consumption Smoothing

This paper analyzes a risk averse entrepreneur's real investment decision under incomplete markets. The entrepreneur smoothes his intertemporal consumption by investing in both a risk-free asset and a risky asset, which allows him to partially hedge against the project cash flow risk. We show that risk aversion lowers both the project value upon investment and the option value of waiting to invest through the precautionary saving effect. Furthermore, risk aversion delays investment since the project value is reduced more than the option value to invest. It is also shown that although hedging can reduce the cash flow risk, it may have a positive or negative return effect, depending on the correlation between the cash flow risk and the market. Consequently, investment timing is not monotonic with the extent of hedging opportunity. Finally, welfare implications of hedging are analyzed.

Online Appendix to "Transitional Dynamics of Dividend and Capital Gains Tax Cuts"

In this appendix, we present the details of the extended model with debt in our paper "Transitional Dynamics of Dividend and Capital Gains Tax Cuts." Section 1 presents the extended model and results. Section 2 presents the numerical algorithm to solve this model. Section 3 presents an extensiongure for the simulation conducted in Section 3 of our original paper.additional

Intertemporal substitution and recursive smooth ambiguity preferences

In this paper, we establish an axiomatically founded generalized recursive smooth ambiguity model that allows for a separation among intertemporal substitution, risk aversion, and ambiguity aversion. We axiomatize this model using two approaches: the second-order act approach à la Klibanoff, Marinacci, and Mukerji (2005) and the two-stage randomization approach à la Seo (2009). We characterize risk attitude and ambiguity attitude within these two approaches. We then discuss our model's application in asset pricing. Our recursive preference model nests some popular models in the literature as special cases.Ambiguity, ambiguity aversion, risk aversion, intertemporal substitution, model uncertainty, recursive utility, dynamic consistency