Correction to “Disasters and
Recoveries”
In
section III of the paper, I analyzed the implications of the disaster model
for the time series predictability of returns. After stating some results
which hold for CRRA utility, I considered how the results would be affected
with Epstein-Zin utility if the probability of disaster is iid (the only
case which can be solved analytically). The underlined part of the
following paragraph needs to be suppressed:
“The natural escape route is to separate
the IES and risk aversion, and to use the IES to control movements in the
risk-free rate. When the disaster probability is iid, i.e. F(p_t+1|p_t)=F(p_t), and risk aversion is greater than
unity, it is possible to show that the result above still applies: the P-D
ratio increasing in the probability of a disaster p if and only if the
elasticity of substitution is less than one, i.e. α>1, the risk premium
is increasing but the equity return is decreasing in the probability of
disaster. Numerical experiments suggest that relaxing the iid
assumption for p does not help significantly.”
It
turns out that even in the case of iid probability, this effect is
ambiguous.
See
my other paper “Time
Series Predictability in the Disaster Model” for a proof and discussion
of these statements in more detail.
This mistake has no impact on
the analysis of recoveries (sections I and II).