We analyze the joint effect of borrowing and short-sale constraints in a dynamic economy populated by two constrained investors with heterogeneous risk aversions and beliefs. We find that equilibrium prices adjust in such a way that the constraints never simultaneously bind. When the constraints are tight, we observe a regime switch behavior (discontinuities) in the risk-free rate and market price of risk at a critical state, where two equilibria exist, i.e., either constraint can be binding. Stock return volatility is the lowest at the critical state. Imposing a ban on short-sales at the same time when access to credit is restrictive or tightening borrowing during a short-sale ban can potentially move the equilibrium away from the critical state, thus increase stock return volatility rather than reducing it.

We study general equilibrium in a Lucas (1978) economy with one consumption good and two investors with heterogeneous risk aversions and beliefs about aggregate consumption growth rate, and portfolio constraints. We provide a comprehensive comparison of various constraints, and show which of them and under what conditions help match the properties of asset prices in the data. We find that borrowing and short-sale constraints decrease stock return volatilities, whereas limited stock market participation constraints can increase volatilities even when investors have identical preferences and beliefs. Moreover, borrowing constraints generate spikes in interest rates and stock return volatilities when the constraint starts to bind. Finally, we find that short-sale constraints have smaller impact on asset prices than borrowing constraints, consistent with the empirical evidence on short-sale bans in the aftermath of 2007-09 financial crisis.

This paper analyzes the effects of portfolio constraints on asset returns and volatility. Portfolio constraints may arise due to minimum capital requirement regulations, margin requirements or leverage constraints on portfolio managers. We analyze how cross-sectional heterogeneity in preferences affect the equilibrium stock price, returns and volatility in the presence of portfolio constraints. We show that portfolio constraints can simultaneously produce high equity Sharpe ratio and low interest rates in equilibrium. Moreover, the stock returns volatility decreases when the constraint binds. The negative effect of the constraint on stock returns volatility is most pronounced when the constraint binds in the bad state of the economy and the unconstrained investor is poorer than the constrained investor. In our model the constraint binds more frequently in the bad states of the economy. Given the empirical evidence in support of the stylized fact that stock returns volatility is counter-cyclical, our findings therefore suggest that margin requirements are indeed effective in mitigating the wild fluctuations in the stock market volatility when prices go low. We also perform a welfare analysis and show that the unconstrained investor is made better off while the constrained is worse off when the constraint binds.

Portfolio constraints are widespread and have significant effects on asset prices. This paper studies the effects of constraints in a dynamic economy populated by investors with different risk aversions and beliefs about the rate of economic growth. The paper provides a comparison of various constraints and conditions under which these constraints help match certain empirical facts about asset prices. Under these conditions, borrowing and short-sale constraints decrease stock return volatilities, whereas limited stock market participation constraints amplify them. Moreover, borrowing constraints generate spikes in interest rates and volatilities and have stronger effects on asset prices than short-sale constraints.

From the field's leading authority, the most authoritative and comprehensive advanced-level textbook on asset pricing In Financial Decisions and Markets, John Campbell, one of the field’s most respected authorities, provides a broad graduate-level overview of asset pricing. He introduces students to leading theories of portfolio choice, their implications for asset prices, and empirical patterns of risk and return in financial markets. Campbell emphasizes the interplay of theory and evidence, as theorists respond to empirical puzzles by developing models with new testable implications. The book shows how models make predictions not only about asset prices but also about investors’ financial positions, and how they often draw on insights from behavioral economics. After a careful introduction to single-period models, Campbell develops multiperiod models with time-varying discount rates, reviews the leading approaches to consumption-based asset pricing, and integrates the study of equities and fixed-income securities. He discusses models with heterogeneous agents who use financial markets to share their risks, but also may speculate against one another on the basis of different beliefs or private information. Campbell takes a broad view of the field, linking asset pricing to related areas, including financial econometrics, household finance, and macroeconomics. The textbook works in discrete time throughout, and does not require stochastic calculus. Problems are provided at the end of each chapter to challenge students to develop their understanding of the main issues in financial economics. The most comprehensive and balanced textbook on asset pricing available, Financial Decisions and Markets is an essential resource for all graduate students and practitioners in finance and related fields. Integrated treatment of asset pricing theory and empirical evidence Emphasis on investors’ decisions Broad view linking the field to financial econometrics, household finance, and macroeconomics Topics treated in discrete time, with no requirement for stochastic calculus Forthcoming solutions manual for problems available to professors

Winner of the prestigious Paul A. Samuelson Award for scholarly writing on lifelong financial security, John Cochrane's Asset Pricing now appears in a revised edition that unifies and brings the science of asset pricing up to date for advanced students and professionals. Cochrane traces the pricing of all assets back to a single idea--price equals expected discounted payoff--that captures the macro-economic risks underlying each security's value. By using a single, stochastic discount factor rather than a separate set of tricks for each asset class, Cochrane builds a unified account of modern asset pricing. He presents applications to stocks, bonds, and options. Each model--consumption based, CAPM, multifactor, term structure, and option pricing--is derived as a different specification of the discounted factor. The discount factor framework also leads to a state-space geometry for mean-variance frontiers and asset pricing models. It puts payoffs in different states of nature on the axes rather than mean and variance of return, leading to a new and conveniently linear geometrical representation of asset pricing ideas. Cochrane approaches empirical work with the Generalized Method of Moments, which studies sample average prices and discounted payoffs to determine whether price does equal expected discounted payoff. He translates between the discount factor, GMM, and state-space language and the beta, mean-variance, and regression language common in empirical work and earlier theory. The book also includes a review of recent empirical work on return predictability, value and other puzzles in the cross section, and equity premium puzzles and their resolution. Written to be a summary for academics and professionals as well as a textbook, this book condenses and advances recent scholarship in financial economics.