Rob's comments made me think some here who aren't on the pk list might be
interested in this.
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From: Trond Andresen [mailto:[EMAIL PROTECTED]] 

The dramatic fall of the NASDAQ to a two year low the last days may be a
forewarning of more than a recession.

In September 98 we had a seminar around a stock market model of mine, see
my opening message for the pkt seminar,
http://csf.colorado.edu/cgi-bin/mfs/55/csf/web/mail/pkt/sep98/0277.html

See also the paper on
http://csf.Colorado.EDU/authors/Andresen.Trond/stock-market.pdf

It seems to me that the behavior of the market since 1998 is a confirmation
of the dynamics predicted in my model. The main behavior demonstrated is a
decade-long cycle. The length of one period is basically decided by the time
for moods (optimist or pessimist) to propagate among agents. Moods are
self-reinforcing both on the upswing and downswing, since mood-driven buying
or selling amplifies the current mood via price change. At the same time
there is a ceiling and a floor for index levels. The ceiling (which
obviously was reached last year) is there because P/E-ratios become very
small so that an even stronger belief in even stronger price appreciation
becomes neccessary for an agent to continue buying. But if they do,
P/E-ratios become even smaller and still stronger price appreciation must be
demanded to compensate for this. Some agents see that this is an unsolvable
scenario and decides that the good times have culminated. They shift to a
bearish trading mood. A larger occurence of selling, even if indices are
still on the rise because the main mood is still optimism, leads to the
appreciation rate starting to weaken. Since this happens in a situation
where agents demand a stronger appreciation rate than ever because their
earnings are negligible or zero, this will lead to more agents understanding
the impossibility of this, and shifting to a selling mood. The
self-reinforcing process from index rise, flattening out, and later starting
to slide, is mercilessly in motion.

Note that we do not need any panic or crash for this to happen. It is a
smooth limit cycle, to use dynamical systems terminology. It occurs beacuse
the model essentially consists of unstable up- and downswings bounded by a
ceiling and a floor. Any panics come on top of these dynamics.

This sluggish, very-large-inertia process is not something stopped
by small interest rate cuts.

I have yet to find related models of long-term stock market dynamics in the
literature. What i have found concerns itself solely with modeling and
explanation of short-term excursions, small bursts and temporary
instabilities around some "efficient" price. I think this is strange. But if
there are models I am not aware of, please inform me.

Trond Andresen

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