4.1.1.5.1. Econometric consequence of transitory earnings.
The econometric
consequence of transitory earnings components is straightforward.A simple
model based on the analysis in Kothari and Zimmerman (1995, Section 5.1)
illustrates the effect.I follow it up with a richer analysis later. Suppose
where Xt is the reported earnings consisting of a random walk component,
xt ¼ xt1 þ et; etBNð0; s2e
Þ and a transitory component, utBNð0; s2u
Þ: Also
assume that the market has no information beyond the time-series property of
earnings and that et and ut are uncorrelated.The earnings response coefficient
on the transitory component is one.How ever, the market’s sensitivity to the
random walk component, i.e., the permanent component of earnings is b ¼
ð1 þ 1=rÞ or the average price–earnings multiple.Usi ng the beginning-ofperiod-
price, Pt1; as the deflator, a return–earnings regression