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.

Does Lumy Investment Matter for Business Cycles?

We present an analytically tractable general equilibrium business cycle model that features micro-level investment lumpiness. We prove an exact irrelevance proposition which provides sufficient conditions on preferences, technology, and the fixed cost distribution such that any positive upper support of the fixed cost distribution yields identical equilibrium dynamics of the aggregate quantities normalized by their deterministic steady state values. We also give two conditions for the fixed cost distribution, under which lumpy investment can be important to a first-order approximation: (i) The steady-state elasticity of the adjustment rate is large so that the extensive margin effect is large. (ii) More mass is on low fixed costs so that the general equilibrium price feedback effect is small. Our theoretical results may reconcile some debate and some numerical findings in the literature.generalized (S,s) rule, lumpy investment, general equilibrium, business cycles, marginal Q, exact irrelevance proposition

Investment, consumption and hedging under incomplete markets

Entrepreneurs often face undiversifiable idiosyncratic risks from their business investments. Motivated by this observation, we extend the standard real options approach to investment to an incomplete markets environment and analyze the joint decisions of business investments, consumption-saving and portfolio selection. We show that precautionary saving motive affects the investment timing decision in an important way. When the investment payoffs are given in lump sum, risk aversion accelerates investment. Moreover, when the agent's precautionary motive is strong enough, an increase in volatility may accelerate investment, opposite to the standard real options analysis. When the agent can trade the market portfolio to partially hedge against his investment risk, the systematic volatility is compensated via the standard CAPM argument, and the idiosyncratic volatility generates a private equity premium. When the investment payoffs are given in flows, the agent's idiosyncratic risk exposure alters both the implied option value and the implied project value, causing the reversal of the results in the lump sum payoff case.real options, idiosyncratic risk, precautionary saving, incomplete markets

Does Lumpy Investment Matter for Business Cycles?

We present an analytically tractable general equilibrium business cycle model that features micro-level investment lumpiness. We prove an exact irrelevance proposition which provides sufficient conditions on preferences, technology, and the fixed cost distribution such that any positive upper support of the fixed cost distribution yields identical equilibrium dynamics of the aggregate quantities normalized by their deterministic steady state values. We also give two conditions for the fixed cost distribution, under which lumpy investment can be important to a first-order approximation: (i) The steady-state elasticity of the adjustment rate is large so that the extensive margin effect is large. (ii) More mass is on low fixed costs so that the general equilibrium price feedback effect is small.generalized (S,s) rule, lumpy investment, general equilibrium, business cycles, marginal Q, exact irrelevance proposition

The perils of credit booms

We present a dynamic general equilibrium model of production economies with adverse selection in the financial market to study the interaction between funding liquidity and market liquidity and its impact on business cycles. Entrepreneurs can take on short-term collateralized debt and trade long-term assets to finance investment. Funding liquidity can erode market liquidity. High funding liquidity discourages firms from selling their good long-term assets since these good assets have to subsidize lemons when there is information asymmetry. This can cause a liquidity dry-up in the market for long-term assets and even a market breakdown, resulting in a financial crisis. Multiple equilibria can coexist. Credit booms combined with changes in beliefs can cause equilibrium regime shifts, leading to an economic crisis or expansion.Published versio