The continuous spin limit of higher spin field equations

We show that the Wigner equations describing the continuous spin representations can be obtained as a limit of massive higher-spin field equations. The limit involves a suitable scaling of the wave function, the mass going to zero and the spin to infinity with their product being fixed. The result allows to transform the Wigner equations to a gauge invariant Fronsdal-like form. We also give the generalisation of the Wigner equations to higher dimensions with fields belonging to arbitrary representations of the massless little group.Comment: 18 pages, JHEP style. Typos corrected, references adde

Expectations Hypotheses Tests

We investigate the Expectations Hypotheses of the term structure of interest rates and of the foreign exchange market using vector autoregressive methods for the U.S. dollar, Deutsche mark, and British pound interest rates and exchange rates. In addition to standard Wald tests, we formulate Lagrange Multiplier and Distance Metric tests which require estimation under the non-linear constraints of the null hypotheses. Estimation under the null is achieved by iterating on approximate solutions that require only matrix inversions. We use a bias-corrected, constrained vector autoregression as a data generating process and construct extensive Monte Carlo simulations of the various test statistics under the null hypotheses. Wald tests suffer from severe size distortions and use of the asymptotic critical values results in gross over-rejection of the null. The Lagrange Multiplier tests slightly under-reject the null, and the Distance Metric tests over-reject. Use of the small sample distributions of the different tests leads to a common interpretation of the validity of the Expectations Hypotheses. The evidence against the Expectations Hypotheses for these interest rates and exchange rates is much less strong than under asymptotic inference.

International Stock Return Comovements

We examine international stock return comovements using country-industry and country-style portfolios. We first establish that parsimonious risk-based factor models capture the covariance structure of the data better than the popular Heston-Rouwenhorst (1994) model. We then establish the following stylized facts regarding stock return comovements. First, we do not find evidence for an upward trend in return correlations, excpet for the European stock markets. Second, the increasing imporatnce of industry factors relative to country factors was a short-lived, temporary phenomenon. Third, we find no evidence for a trend in idiosyncratic risk in any of the countries we examine.

International stock return comovements

We examine international stock return comovements using country-industry and country-style portfolios as the base portfolios. We first establish that parsimonious risk-based factor models capture the covariance structure of the data better than the popular Heston- ouwenhorst (1994) model. We then establish the following stylized facts regarding stock return comovements. First, we do not find evidence for an upward trend in return correlations, except for the European stock markets. Second, the increasing importance of industry factors relative to country factors was a short-lived, temporary phenomenon. JEL Classification: C52, G11, G12APT model, Comovements, correlation dynamics, Factor models, global market integration, industry country debate, international diversification

"Peso Problem" Explanations for Term Structure Anomalies

We examine the empirical evidence on the expectations hypothesis of the term structure of interest rates in the United States, the United Kingdom, and Germany using the Campbell-Shiller (1991) regressions and a vector-autoregressive" methodology. We argue that anomalies in the U.S. term structure, documented by Campbell and Shiller (1991), may be due to a generalized peso problem in which a high-interest rate regime occurred less frequently in the sample of U.S. data than was rationally anticipated. We formalize this idea as a regime-switching model of short-term interest rates estimated with data" from seven countries. Technically, this model extends recent research on regime-switching models with state-dependent transitions to a cross-sectional setting. Use of the small sample distributions generated by the regime-switching model for inference considerably weakens the evidence against the expectations hypothesis, but it remains somewhat implausible that our data-generating process produced the U.S. data. However, a model that combines moderate time-variation in term premiums with peso-problem effects is largely consistent with term structure data from the U.S., U.K., and Germany.

The Implications of First-Order Risk Aversion for Asset Market Risk Premiums

Existing general equilibrium models based on traditional expected utility preferences have been unable to explain the excess return predictability observed in equity markets, bond markets, and foreign exchange markets. In this paper, we abandon the expected-utility hypothesis in favor of preferences that exhibit first-order risk aversion. We incorporate these preferences into a general equilibrium two-country monetary model, solve the model numerically, and compare the quantitative implications of the model to estimates obtained from U.S. and Japanese data for equity, bond and foreign exchange markets. Although increasing the degree of first-order risk aversion substantially increases excess return predictability, the model remains incapable of generating excess return predictability sufficiently large to match the data. We conclude that the observed patterns of excess return predictability are unlikely to be explained purely by time-varying risk premiums generated by highly risk averse agents in a complete markets economy.

"Peso problem" explanations for term structure anomalies

We examine the empirical evidence on the expectation hypothesis of the term structure of interest rates in the United States, the United Kingdom, and Germany using the Campbell-Shiller (1991) regressions and a vector-autoregressive methodology. We argue that anomalies in the U.S. term structure, documented by Campbell and Shiller (1991), may be due to a generalized peso problem in which a high-interest rate regime occurred less frequently in the sample of U.S. data than was rationally anticipated. We formalize this idea as a regime-switching model of short-term interest rates estimated with data from seven countries. Technically, this model extends recent research on regime-switching models with state-dependent transitions to a cross-sectional setting. Use of the small sample distributions generated by regime-switching model for inference considerably weakens the evidence against the expectations hypothesis, but it remains somewhat implausible that our data-generating process produced the U.S. data. However, a model that combines moderate time-variation in term premiums with peso-problem effects is largely consistent with term-structure data from the U.S., U.K., and Germany.Interest rates ; Econometric models

Global Crises and Equity Market Contagion

Using the 2007-09 financial crisis as a laboratory, we analyze the transmission of crises to country-industry equity portfolios in 55 countries. We use a factor model to predict crisis returns, defining unexplained increases in factor loadings and residual correlations as indicative of contagion. We find statistically significant evidence of contagion from US markets and from the global financial sector, but the effects are economically small. By contrast, there has been substantial contagion from domestic equity markets to individual domestic equity portfolios, with its severity inversely related to the quality of countries’ economic fundamentals and policies. This confirms the old “wake-up call” hypothesis, with markets and investors focusing substantially more on country-specific characteristics during the crisis.