Mortgage convexity

Most home mortgages in the United States are fixed-rate loans with an embedded prepayment option. When long-term rates decline, the effective duration of mortgage-backed securities (MBS) falls due to heightened refinancing expectations. I show that these changes in MBS duration function as large-scale shocks to the quantity of interest rate risk that must be borne by professional bond investors. I develop a simple model in which the risk tolerance of bond investors is limited in the short run, so these fluctuations in MBS duration generate significant variation in bond risk premia. Specifically, bond risk premia are high when aggregate MBS duration is high. The model offers an explanation for why long-term rates could appear to be excessively sensitive to movements in short rates and explains how changes in MBS duration act as a positive-feedback mechanism that amplifies interest rate volatility. I find strong support for these predictions in the time series of US government bond returns.     

The cross-sectional relation between conditional heteroskedasticity,the implied volatility smile,and the variance risk premium

This paper estimates how the shape of the implied volatility smile and the size of the variance risk premium relate to parameters of GARCH-type time-series models measuring how conditional volatility responds to return shocks. Markets in which return shocks lead to large increases in conditional volatility tend to have larger variance risk premia than markets in which the impact on conditional volatility is slight. Markets in which negative (positive) return shocks lead to larger increases in future volatility than positive (negative) return shocks tend to have downward (upward) sloping implied volatility smiles. Also, differences in how volatility responds to return shocks as measured by GARCH-type models explain much, but not all, of the variations in excess kurtosis and multi-period skewness across different markets.     

Sensitivity of the bank stock returns distribution to changes in the level and volatility of interest rate: A GARCH-M model

The objective of this paper is to employ the generalized autoregressive conditionally heteroskedastic in the mean (GARCH-M) methodology to investigate the effect of interest rate and its volatility on the bank stock return generation process. This framework discards the restrictive assumptions of linearity, independence, and constant conditional variance in modeling bank stock returns. The model presented here allows for shifts in the volatility equation in response to the changes in monetary policy regime in 1979 and 1982 to be estimated. ARCH, GARCH, and volatility feed back effects are found to be significant. Interest rate and interest rate volatility are found to directly impact the first and the second moments of the bank stock returns distribution, respectively. The latter also affects the risk premia indirectly. The degree of persistence in shocks is substantial for all the three bank portfolios and sensitive to the nature of the bank portfolio and the prevailing monetary policy regime.     

Why do firm fundamentals predict returns? Evidence from short selling activity

This study uses short selling activity to test whether the relation between fundamentals and future returns is due to rational pricing or mispricing. We find that short sellers target firms with fundamental performance below market expectations. We also show that short selling activity reduces the return predictability of fundamentals by speeding up the price adjustments to negative fundamental signals. To further investigate whether the returns earned by short sellers reflect rational risk premia or mispricing, we exploit a natural experiment, namely Regulation of SHO, which creates exogenous shocks to short selling by temporarily relaxing short-sale constraints. Evidence from the experiment confirms that the superior returns to short sellers result from exploiting overpricing. Overall, our study suggests that the return predictability of fundamentals reflects mispricing rather than rational risk premia.     

Tails,Fears, and Risk Premia

We show that the compensation for rare events accounts for a large fraction of the average equity and variance risk premia. Exploiting the special structure of the jump tails and the pricing thereof, we identify and estimate a new Investor Fears index. The index reveals large time‐varying compensation for fears of disasters. Our empirical investigations involve new extreme value theory approximations and high‐frequency intraday data for estimating the expected jump tails under the statistical probability measure, and short maturity out‐of‐the‐money options and new model‐free implied variation measures for estimating the corresponding risk‐neutral expectations.     

The Impact of the Volatility of Monetary Policy Shocks

This paper studies the impact of the volatility of monetary policy using a structural vector auroregression (SVAR) model enriched along two dimensions. First, it allows for time‐varying variance of monetary policy shocks via a stochastic volatility specification. Second, it allows a dynamic interaction between the level of the endogenous variables in the VAR and the time‐varying volatility. The analysis establishes that the nominal interest rate, output growth, and inflation fall in reaction to an increase in the volatility of monetary policy. The analysis also develops a dynamic stochastic general equilibrium model enriched with stochastic volatility to monetary policy that generates similar responses and provides a theoretical underpinning of these findings.     

TIME-VARYING TERM PREMIA AND THE BEHAVIOR OF FORWARD INTEREST RATE PREDICTION ERRORS

In this paper I examine the time-varying expected term premium argument for the failure of the expectations hypothesis of the term structure of U.S. interest rates. Using an unobserved components model to estimate expected term premia from March 1951 to January 1991, I find considerable variation in estimated premia and significant persistence in their volatility over time.     

Monetary policy and aggregate volatility

Discretionary conduct of monetary stabilization policy can increase real and nominal aggregate volatility by arbitrary amounts when firms pay limited attention to aggregate shocks. A conservative central banker with stronger preference for price stability eliminates the commitment problem, thereby reduces output and price volatility and gives rise to a policy-induced ‘Great Moderation’. Increased focus on price stability facilitates firms’ information processing and aligns their expectations better with policy decisions. This ‘coordination effect’ reduces aggregate real and nominal volatility. Consistent with empirical evidence, the moderation manifests itself through reduced residual variance in vector autoregressions (VARs) involving macroeconomic variables.     

Maximum likelihood estimation of non-affine volatility processes

In this paper we develop a new estimation method for extracting non-affine latent stochastic volatility and risk premia from measures of model-free realized and risk-neutral integrated volatility. We estimate non-affine models with nonlinear drift and constant elasticity of variance and we compare them to the popular square-root stochastic volatility model. Our empirical findings are: (1) the square-root model is misspecified; (2) the inclusion of constant elasticity of variance and nonlinear drift captures stylized facts of volatility dynamics and (3) the square-root stochastic volatility model is explosive under the risk-neutral probability measure.     

The Share of Systematic Variation in Bilateral Exchange Rates

Sorting countries by their dollar currency betas produces a novel cross section of average currency excess returns. A slope factor (long in high beta currencies and short in low beta currencies) accounts for this cross section of currency risk premia. This slope factor is orthogonal to the high‐minus‐low carry trade factor built from portfolios of countries sorted by their interest rates. The two high‐minus‐low risk factors account for 18% to 80% of the monthly exchange rate movements. The two risk factors suggest that stochastic discount factors in complete markets' models should feature at least two global shocks to describe exchange rates.     

An Anatomy of Commodity Futures Risk Premia

We identify two types of risk premia in commodity futures returns: spot premia related to the risk in the underlying commodity, and term premia related to changes in the basis. Sorting on forecasting variables such as the futures basis, return momentum, volatility, inflation, hedging pressure, and liquidity results in sizable spot premia between 5% and 14% per annum and term premia between 1% and 3% per annum. We show that a single factor, the high‐minus‐low portfolio from basis sorts, explains the cross‐section of spot premia. Two additional basis factors are needed to explain the term premia.     

Time‐Varying Asset Volatility and the Credit Spread Puzzle

Most extant structural credit risk models underestimate credit spreads—a shortcoming known as the credit spread puzzle. We consider a model with priced stochastic asset risk that is able to fit medium‐ to long‐term spreads. The model, augmented by jumps to help explain short‐term spreads, is estimated on firm‐level data and identifies significant asset variance risk premia. An important feature of the model is the significant time variation in risk premia induced by the uncertainty about asset risk. Various extensions are considered, among them optimal leverage and endogenous default.     

Heterogeneous Beliefs, the Term Structure and Time-varying Risk Premia

This paper demonstrates theoretically and empirically that one possible economic explanation of the dynamics of the term structure of interest rates is the time-varying heterogeneous beliefs about future economic conditions. Assuming that each agent forms heterogeneous expectations about both his income shock and others’ beliefs about their income shocks each period, the paper illustrates that heterogeneous beliefs generate time-varying risk premia of the term structure in a closed-form solution. Motivated by this theory, several empirical tests are conducted using the cross-sectional mean and dispersion of belief indices that are extracted as the differences between non-judgemental econometric forecasts based on diffusion indices in Stock and Watson (J Bus Econ Stat, 2002) and professional survey forecasts. It is shown that (a) an increase in the mean belief about inflation steepens the yield curve, (b) the mean and dispersion of interest rate beliefs help explain the mean and the stochastic volatility of the term structure, suggesting that time-varying risk premia may be explained by endogenous uncertainty caused by heterogeneous beliefs in the economy.I am indebted to Mordecai Kurz, Timothy Cogley and Narayana Kocherlakota for constant support and extensive discussions that inspired this work. I would like to thank Randall Moore for providing the Blue Chip financial forecast data. The financial support from the Smith Richardson Foundation to the Stanford Institute for Economic Policy Research is gratefully acknowledged.     

Do Banks Affect the Level and Composition of Industrial Volatility?

In theory, better access to bank credit can reduce or increase output volatility depending on whether firms are more financially constrained during contractions or expansions. This paper finds that the volatility of industrial output is lower in countries with more bank credit. Most of the reduction in volatility is idiosyncratic, which follows from the ability of banks to pool and diversify shocks. Systematic volatility is reduced less strongly. Volatility dampening is achieved via countercyclical borrowing: At the firm level, short‐term borrowing is less (or more negatively) correlated with sales and inventories in countries with high levels of bank credit.     

On Monetary Policy and Stock Market Anomalies

This study utilizes a macro‐based VAR framework to investigate whether stock portfolios formed on the basis of their value, size and past performance characteristics are affected in a different manner by unexpected US monetary policy actions during the period 1967–2007. Full sample results show that value, small capitalization and past loser stocks are more exposed to monetary policy shocks compared with growth, big capitalization and past winner stocks. Sub‐sample analysis, motivated by variation in the realized premia and parameter instability, reveals that the impact of monetary policy shocks on these portfolios is significant and pronounced only during the pre‐1983 period.     

When units roots matter: excess volatility and excess smoothness of long-term interest rates

This paper re-examines volatility tests of the expectations model of the term structure of interest rates. In a multivariate vector autoregression (VAR) including interest rates, prices, money and output, we find that the long-term interest rate overreacts to all transitory shocks, and underreacts to all permanent shocks, irrespective of the number of unit roots and the cointegration structure in the system.     

Explaining the Magnitude of Liquidity Premia: The Roles of Return Predictability,Wealth Shocks,and State‐Dependent Transaction Costs

Constantinides (1986) documents how the impact of transaction costs on per‐annum liquidity premia in the standard dynamic allocation problem with i.i.d. returns is an order of magnitude smaller than the cost rate itself. Recent papers form portfolios sorted on liquidity measures and find spreads in expected per‐annum return that are the same order of magnitude as the transaction cost spread. When we allow returns to be predictable and introduce wealth shocks calibrated to labor income, transaction costs are able to produce per‐annum liquidity premia that are the same order of magnitude as the transaction cost spread.     

Evaluation of long-dated assets: The role of parameter uncertainty

Under expected utility, the uncertainty that affects the parameters of the random walk of consumption growth has no effect on the value of short-term claims and makes the term structure of risk-free rates decreasing. The term structure of aggregate risk premia is increasing when the uncertain cumulants of log consumption are independent. We apply these generic results to the case of an uncertain probability of catastrophes, and to the case of an uncertain trend or volatility of growth. Adding some persistence to unobservable shocks into our benchmark model, we show that the term structure of risk premia is hump-shaped.     

Credit default swap spreads and variance risk premia

We find that the firm-level variance risk premium has a prominent explanatory power for credit spreads in the presence of market- and firm-level control variables established in the existing literature. Such predictability complements that of the leading state variable—the leverage ratio—and strengthens significantly with a lower firm credit rating, longer credit contract maturity, and model-free implied variance. We provide further evidence that (1) the variance risk premium has a cleaner systematic component than implied variance or expected variance, (2) the cross-section of firms’ variance risk premia capture systematic variance risk in a stronger way than firms’ equity returns in capturing market return risk, and (3) a structural model with stochastic volatility can reproduce the predictability pattern of variance risk premia for credit spreads.     

The intertemporal volatility structure of Euro CD rates

In this paper we examine the intertemporal volatility structure of Eurocurrency rates of five different maturities ranging from seven days to twelve months for six Euro CD currency denominations spanning the 1986–1992 period. the analysis used the common ARCH-feature testing methodology recently developed by Engle and Kozicki (1993). First, the results indicate presence of ARCH effects in the Eurocurrency rate series. This result suggests that modelling of Eurocurrency rates requires the inclusion of time-varying risk premia. Second, our evidence reveals that short- and long-term Eurocurrency rate series have the same volatility process. the results point out that a common time-varying volatility process characterises most Eurocurrency rate series across maturities and currency denominations. Hence, the common ARCH results imply that a common time-varying variance model would be the appropriate specification of the conditional heterscedasticity for most Eurocurrency rates.