AUTOMOBILE FUEL ECONOMY: WHAT IS IT WORTH?

The marginal value of increased automobile fuel economy is estimated using a hedonic model of 2001 model year automobiles sold in the United States. This value is then compared to the average expected lifetime fuel savings attributable to increased fuel economy. Results indicate that automobile buyers fully internalize fuel cost savings attributable to improved fuel economy at low discount rates, and may partially internalize other perceived benefits of improved fuel economy such as reduction in global warming or fossil fuel dependence.     

Interpreting Factor Models

We argue that tests of reduced‐form factor models and horse races between “characteristics” and “covariances” cannot discriminate between alternative models of investor beliefs. Since asset returns have substantial commonality, absence of near‐arbitrage opportunities implies that the stochastic discount factor can be represented as a function of a few dominant sources of return variation. As long as some arbitrageurs are present, this conclusion applies even in an economy in which all cross‐sectional variation in expected returns is caused by sentiment. Sentiment‐investor demand results in substantial mispricing only if arbitrageurs are exposed to factor risk when taking the other side of these trades.