This study examines common stock prices around ex-dividend dates. Such price data usually contain a mixture of observations—some with and some without arbitrageurs and/or dividend capturers active. Our theory predicts that such mixing will result in some nonlinear relation between percentage price drop and dividend yield—not the commonly assumed linear relation. This prediction and another important prediction of theory are supported empirically. In a variety of tests, marginal price drop is not significantly different from the dividend amount. Thus, over the last several decades, one-for-one marginal price drop has been an excellent (average) rule of thumb.

In empirical studies of the CAPM, it is commonly assumed that (a) the return to the value weighted portfolio of all stocks is a reasonable proxy for the return on the market portfolio of all assets in the economy, and (b) betas of assets remain constant over time. Under these assumptions, Fama and French (1992) find that the relation between average return and beta is flat. We argue that these two auxiliary assumptions are not reasonable. We demonstrate that when these assumptions are relaxed, the empirical support for the CAPM is surprisingly strong. When human capital is also included in measuring wealth, the CAPM is able to explain 28 percent of the cross sectional variation in average returns in the 100 portfolios studied by Fama and French. When, in addition, betas are allowed to vary over the business cycle, the CAPM is able to explain 57 percent. More important, relative size does not explain what is left unexplained after taking sampling errors into account.

In empirical studies of the CAPM, it is commonly assumed that (a) the return to the value weighted portfolio of all stocks is a reasonable proxy for the return on the market portfolio of all assets in the economy, and (b) betas of assets remain constant over time. Under these assumptions, Fama and French (1992) find that the relation between average return and beta is flat. We argue that these two auxiliary assumptions are not reasonable. We demonstrate that when these assumptions are relaxed, the empirical support for the CAPM is surprisingly strong. When human capital is also included in measuring wealth, the CAPM is able to explain 28 percent of the cross sectional variation in average returns in the 100 portfolios studied by Fama and French. When, in addition, betas are allowed to vary over the business cycle, the CAPM is able to explain 57 percent. More important, relative size does not explain what is left unexplained after taking sampling errors into account.

We provide empirical evidence of a novel liquidity-based transmission mechanism through which monetary policy influences asset markets, develop a model of this mechanism, and assess the ability of the quantitative theory to match the evidence.

Time-varying risk is the primary force driving nominal interest rate differentials on currency-denominated bonds. This finding is an immediate implication of the fact that exchange rates are roughly random walks. We show that a general equilibrium monetary model with an endogenous source of risk variation—a variable degree of asset market segmentation—can produce key features of actual interest rates and exchange rates. The endogenous segmentation arises from a fixed cost for agents to exchange money for assets. As inflation varies, the benefit of asset market participation varies, and that changes the fraction of agents participating. These effects lead the risk premium to vary systematically with the level of inflation. Our model produces variation in the risk premium even though the fundamental shocks have constant conditional variances.

U.S. stock prices have increased much faster than gross domestic product GDP) in the postwar period. Between 1962 and 2000, corporate equity value relative to GDP nearly doubled. In this paper, we determine what standard growth theory says the equity value should be in 1962 and 2000, the two years for which our steady-state assumption is a reasonable one. We find that the actual valuations were close to the theoretical predictions in both years. The reason for the large run-up in equity value relative to GDP is that the average tax rate on dividends fell dramatically between 1962 and 2000. We also find that, given legal constraints that effectively prohibited the holding of stocks as reserves for pension plans, there is no equity premium puzzle in the postwar period. The average returns on debt and equity are as theory predicts.

The neoclassical growth model is extended to include costly intermediated borrowing and lending between households. This is an important extension as substantial resources are used in intermediating the large amount of borrowing and lending between households. In 2007, in the United States, the amount intermediated was 1.7 times GNP, and the resources used in this intermediation amounted to at least 3.4 percent of GNP. The theory implies that financial intermediation services are an intermediate good and that the spread between borrowing and lending rates measures the efficiency of the financial sector.

There is a large amount of intermediated borrowing and lending between households. Some of it is intergenerational, but most is between older households. The average difference in borrowing and lending rates is over 2 percent. In this paper, we develop a model economy that displays these facts and matches not only the returns on assets but also their quantities. The heterogeneity giving rise to borrowing and lending and differences in equity holdings depends on differences in the strength of the bequest motive. In equilibrium, the lenders are annuity holders and the borrowers are those who have equity holdings, who live off its income when retired, and who leave a bequest. The borrowing rate and return on equity are the same in the absence of aggregate uncertainty. The divergence between borrowing and lending rates can thus give rise to an equity premium, even in a world without aggregate uncertainty.

The financialization view is that increased trading in commodity futures markets is associated with increases in the growth rate and volatility of commodity spot prices. This view gained credence be-cause in the 2000s trading volume increased sharply and many commodity prices rose and became more volatile. Using a large panel dataset we constructed, which includes commodities with and with-out futures markets, we find no empirical link between increased futures market trading and changes in price behavior. Our data sheds light on the economic role of futures markets. The conventional view is that futures markets provide one-way insurance by allowing outsiders, traders with no direct interest in a commodity, to insure insiders, traders with a direct interest. The data are not consistent with the conventional view and we argue that they point to an alternative mutual insurance view, in which all participants insure each other. We formalize this view in a model and show that it is consistent with key features of the data.

We develop a new general equilibrium model of asset pricing and asset trading volume in which agents’ motivations to trade arise due to uninsurable idiosyncratic shocks to agents’ risk tolerance. In response to these shocks, agents trade to rebalance their portfolios between risky and riskless assets. We study a positive question — When does trade volume become a pricing factor? — and a normative question — What is the impact of Tobin taxes on asset trading on welfare? In our model, economies in which marketwide risk tolerance is negatively correlated with trade volume have a higher risk premium for aggregate risk. Likewise, for a given economy, we find that assets whose cash flows are concentrated on states with high trading volume have higher prices and lower risk premia. We then show that Tobin taxes on asset trade have a first-order negative impact on ex-ante welfare, i.e., a small subsidy to trade leads to an improvement in ex-ante welfare. Finally, we develop an alternative version of our model in which asset trade arises from uninsurable idiosyncratic shocks to agents’ hedging needs rather than shocks to their risk tolerance. We show that our positive results regarding the relationship between trade volume and asset prices carry through. In contrast, the normative implications of this specification of our model for Tobin taxes or subsidies depend on the specification of agents’ preferences and non-traded endowments.

This paper argues that the comovement between inflation and economic activity is an important determinant of real interest rates over time and across countries. First, we show that for advanced economies, periods with more procyclical inflation are associated with lower real rates, but only when there is no risk of default on government debt. Second, we present a model of nominal sovereign debt with domestic risk-averse lenders. With procyclical inflation, nominal bonds pay out more in bad times, making them a good hedge against aggregate risk. In the absence of default risk, procyclical inflation yields lower real rates. However, procyclicality implies that the government needs to make larger (real) payments when the economy deteriorates, which could increase default risk and trigger an increase in real rates. The patterns of real rates predicted by the model are quantitatively consistent with those documented in the data.

This chapter is an introductory essay to the volume Climate Change Economics: The Role of Uncertainty and Risk, edited by V. V. Chari and Robert Litterman. This volume consists of a collection of papers that were presented at "The Next Generation of Economic Models of Climate Change," a conference hosted by the Heller-Hurwicz Economics Institute at the University of Minnesota.

We investigate how trading frictions in asset markets affect portfolio choices, asset prices and efficiency. We generalize the search-theoretic model of financial intermediation of Duffie, Gârleanu and Pedersen (2005) to allow for more general preferences and idiosyncratic shock structure, unrestricted portfolio choices, aggregate uncertainty and entry of dealers. With a fixed measure of dealers, we show that a steady-state equilibrium exists and is unique, and provide a condition on preferences under which a reduction in trading frictions leads to an increase in the price of the asset. We also analyze the effects of trading frictions on bid-ask spreads, trade volume and the volatility of asset prices, and find that the asset allocation is constrained-inefficient unless investors have all the bargaining power in bilateral negotiations with dealers. We show that the dealers’ entry decision introduces a feedback that can give rise to multiple equilibria, and that free-entry equilibria are generically inefficient.

I develop an asset-pricing model in which financial assets are valued for their liquidity—the extent to which they are useful in facilitating exchange—as well as for being claims to streams of consumption goods. The implications for average asset returns, the equity-premium puzzle and the risk-free rate puzzle, are explored in a version of the model that nests the work of Mehra and Prescott (1985).

Under mild assumptions, the data indicate that fluctuations in nominal interest rate differentials across currencies are primarily fluctuations in time-varying risk. This finding is an immediate implication of the fact that exchange rates are roughly random walks. If most fluctuations in interest differentials are thought to be driven by monetary policy, then the data call for a theory which explains how changes in monetary policy change risk. Here we propose such a theory based on a general equilibrium monetary model with an endogenous source of risk variation—a variable degree of asset market segmentation.

This paper measures the output costs of sovereign risk by combining a sovereign debt model with firm- and bank-level data. In our framework, an increase in sovereign risk lowers the price of government debt and has an adverse impact on banks’ balance sheets, disrupting their ability to finance firms. Importantly, firms are not equally affected by these developments: those that have greater financing needs and borrow from banks that are more exposed to government debt cut their production the most in a debt crisis. We measure the extent of this heterogeneity using Italian data and parameterize the model to match these cross-sectional facts. In counterfactual analysis, we find that heightened sovereign risk was responsible for one-third of the observed output decline during the 2011-2012 crisis in Italy.

We develop an asset pricing model with flexible heterogeneity in asset demand across investors, designed to match institutional and household holdings. A portfolio choice model implies characteristics-based demand when returns have a factor structure and expected returns and factor loadings depend on the assets' own characteristics. We propose an instrumental variables estimator for the characteristics-based demand system to address the endogeneity of demand and asset prices. Using U.S. stock market data, we illustrate how the model could be used to understand the role of institutions in asset market movements, volatility, and predictability.