Suchergebnisse

"We propose a new model of exchange rates, which yields a theory of the forward premium puzzle. Our explanation combines two ingredients: the possibility of rare economic disasters, and an asset view of the exchange rate. Our model is frictionless, has complete markets, and works for an arbitrary number of countries. In the model, rare worldwide disasters can occur and affect each country's productivity. Each country's exposure to disaster risk varies over time according to a mean-reverting process. Risky countries command high risk premia: they feature a depreciated exchange rate and a high interest rate. As their risk premium mean reverts, their exchange rate appreciates. Therefore, currencies of high interest rate countries appreciate on average. To make the notion of disaster risk more implementable, we show how options prices might in principle uncover latent disaster risk, and help forecast exchange rate movements. We then extend the framework to incorporate two factors: a disaster risk factor, and a business cycle factor. We calibrate the model and obtain quantitatively realistic values for the volatility of the exchange rate, the forward premium puzzle regression coefficients, and near-random walk exchange rate dynamics. Finally, we solve a model of stock markets across countries, which yields a series of predictions about the joint behavior of exchange rates, bonds, options and stocks across countries. The evidence from the options market appears to be supportive of the model"--National Bureau of Economic Research web site

A representative-consumer model with Epstein-Zin-Weil preferences and i.i.d. shocks, including rare disasters, accords with observed equity premia and risk-free rates if the coefficient of relative risk aversion equals 3–4. If the intertemporal elasticity of substitution exceeds one, an increase in uncertainty lowers the price-dividend ratio for equity, and a rise in the expected growth rate raises this ratio. Calibrations indicate that society would willingly reduce GDP by around 20 percent each year to eliminate rare disasters. The welfare cost from usual economic fluctuations is much smaller, though still important, corresponding to lowering GDP by about 1.5 percent each year. (JEL E13, E21, E22, E32)

"A representative-consumer model with Epstein-Zin-Weil preferences and i.i.d. shocks, including rare disasters, accords with key asset-pricing observations. If the coefficient of relative risk aversion equals 3-4, the model accords with observed equity premia and risk-free real interest rates. If the intertemporal elasticity of substitution is greater than one, an increase in uncertainty lowers the price-dividend ratio for equity, whereas a rise in the expected growth rate raises this ratio. In a model with endogenous saving, more uncertainty lowers the saving ratio (because substitution effects dominate). The match with major features of asset pricing suggests that the model is a reasonable candidate for assessing the welfare cost of aggregate consumption uncertainty. In the baseline simulation, the welfare cost of disaster risk is large -- society would be willing to lower real GDP by as much as 20% each year to eliminate the small chance of major economic collapses. The welfare cost from usual economic fluctuations is much smaller, though still important, corresponding to lowering GDP by around 1.5% each year"--National Bureau of Economic Research web site

TheStern Review's evaluation of environmental protection stresses low discount rates and uncertainty about environmental effects. An appropriate model for analysing this uncertainty and the associated discount rates requires sufficient risk aversion and fat‐tailed uncertainty to account for the observed equity premium. Calibrations based on Epstein–Zin preferences and existing analyses of rare macroeconomic disasters suggest that optimal environmental investment can be a significant share of GDP even with reasonable rates of time preference. Optimal environmental investment increases with risk aversion and the probability and typical size of environmental disasters, but decreases with uncertainty about policy effectiveness.