Stock market dispersion and business cycles
This article looks at another way to analyze
stock price data that can help forecast
business cycles. This kind of analysis is motivated
by Black (1987, p. 113-114) who argued
that the behavior of an industry's stock price
can be used to forecast the industry's subsequent
investment expenditures. Increases in an
industry's stock price are generally followed
by an increase in that industry's expenditures
on plant and equipment. If stock prices are
increasing in some industries but declining in
others, it suggests that in subsequent years
capital and labor will have to be reallocated
from the contracting industries to the expanding
ones. While beneficial in the long run, this
reallocation of resources imposes short-run
costs, that is, temporary declines in real activity
as the resources move across industries.
The greater the divergence in the fortunes of
different industries, the more resources must
be moved, and so the larger will be the resulting
unemployment and fall in output.