1990_First-order risk aversion and the equity premium puzzle_Larry G.Epstein and Stanley E. Zin.pdf
文本预览下载声明
Journal of Monetary Economics 26 (1990) 387-407. North-Holland
‘First-order’ risk aversion and
the equity premium puzzle*
Larry G. Epstein
Unwerslty of Toronto, Toronto, Ont. M5S IAI, Canada
Stanley E. Zin
Carnep Mellon Umlws~ty. Ptttshurgh, PA 15213, USA
Recerved September 1989, final versron received June 1990
This paper Integrates Yaari’s dual theory of choice under uncertamty into a multiperiod context
and examines its imphcations for the equity premium puzzle. An Important property of these
preferences IS that of ‘tirst-order risk aversion’ which implies. in our model. that the risk
premium for a small gamble is proportronal to the standard deviation rather than the variance.
Since the standard devration of the growth rate m aggregate consumptron is considerably larger
than Its varrance, the model can generate both a small rusk-free rate and a moderate equity
premmm.
1. Introduction
It is common practice in macroeconomics and finance to employ a repre-
sentative agent model in order to organize aggregate data on consumption
and asset returns. Because of the smoothness of aggregate consumption data
for the U.S., the way in which the agent’s risk preferences evaluate small
gambles about certainty is critical for providing a good fit to the data. On the
other hand, the plausibility of utility specifications is often evaluated infor-
mally on the basis of their evaluation of moderate or large gambles derived
from thought experiments or ‘real world’ risks. Thus it is desirable to have a
functional form for risk preferences which can model plausible risk attitudes
*We are indebted to Chew Soo Hong and Uzi Segal for valuable discussrons. We have also
benefited from comments by Phrllipe Weil and semmar partrcipants at the Federal Reserve Bank
of Minneapohs, Stanford Universtty. the Natronal Bureau of Economrc Research, Queen’s
University, and Northwestern Universtty. The first author gratefully acknowledges the financial
support of the Soci
显示全部