Uma rápida procura e acharemos trabalhos científicos sobre as diversas falácias da análise técnica e fundamentalista.
Seja tentando copiar o incopiável (Buffet), que com todo seu cacife elege boa parte do conselho, seja usando termos bonitos como VaR, amplamente aplicado pelos Prêmios Nobel do LTCM, que quebrou e quase levou o mundo junto (santo Taleb!), é possível apontar falhas em ambas.
Mas pra não pegar pesado, pois poucos tem tempo para ler monografias e teses longas e enfadonhas, sugiro a leitura do artigo abaixo, que indica um meio termo que me parece muito mais inteligente
Fundamental analysis, technical analysis, and psycho‐fundamental analysis are not
particularly reliable on their own merits. In the case of fundamental analysis we can’t
trust the numbers because they might be misrepresented or fraudulent. The primary
problem with technical analysis is that any of the chart patterns we use in determining
entry and exit points can be either randomly occurring and as the result meaningless, or
constitute a trap because somebody is manipulating the stocks price. Psychofundamental
analysis is simply much too subjective to be useful by itself except in rare
Due to the peculiar human propensity to disdain logic and reason (particularly when
embracing them might require effort) and opt for a position at the extreme (where
lassitude is readily accepted), the world of stock analysis has devolved into two
primary camps: Fundamentalists and Technicians.
The Fundamentalists favor donning eyeshades, clutching calculators and digging
endlessly through financial statements in the belief that they can determine a
company’s “intrinsic” value; once they do that, it’s just a matter of finding a company
whose value is greater than its stock’s current price. Voila! A winner! This belief springs
from the presumption that the market will eventually recognize that the stock is
undervalued and bid the price up to the point that the analyst in his great wisdom has
concluded is proper. Ah, would that life were so easy and the markets so rational!
The first problem is that when attempting to ascribe intrinsic value one needs to make
quite a number of assumptions – not the least of which is that the numbers being used
are accurate. While there is a rather significant amount of “group‐think” in evidence
throughout the Fundamentalist set, the fact is that everyone’s assumptions tend to be
different, and so the valuations tend to vary, sometimes markedly so.
The second problem is that the Road to Hell is littered with the stock certificates of
extinct “undervalued” companies that the market ultimately determined weren’t
anywhere near undervalued enough.
Die‐hard Fundamentalists are also inclined to dismiss technical analysis as nothing
more than the “mumbo‐jumbo” interpretation of bird scratchings or equate it to the
divining of scattered chicken bones by Voodun priests. Despite its shortcomings and
those of its frequently rigid practitioners, fundamental analysis is a predictive and
consistent enough discipline to retain most of its disciples.
Technicians prefer the opposite extreme. Unlike Fundamentalists, Technicians act on
the assumption that everything that is known about a company’s financial condition
has already been recognized and widely disseminated by the fundamentalists, and
hence (because the Fundamentalists comprise the larger of the two cults), this
information has already been factored into the stock’s price. Thus, there is little point in
wasting time in the tedious perusal of financial statements when there is so much more
fun to be had playing with a stock chart as if it was a ouiji board.
There is some validity in the Technicians’ presumption of knowledge being factored into
the price, just as there is some validity in the Fundamentalists’ presumption that an
“undervalued” stock will more reliably provide gains than one that is overvalued.
Though the Technicians’ premise works well enough often enough to keep them in
business, it too has a couple of serious flaws. Both spring from the presumption that one
can trust the chart.
Unfortunately, a stock chart is no more reliable than a financial statement. Software
developers who create stock charting software have demonstrated that when checking
their work by using random numbers every chart pattern known to man will appear on
the sample chart: Cup with Handle, Head and Shoulders, Flags, Pennants, Saucer with
Handle, Triangles, and Stair‐steps. How can anyone rationally invest their money when
confronted with that? To make matters worse, there are people wealthy enough and
wily enough, who understand technical analysis and technicians well enough, that they
will manipulate the price of a stock in order to lure in the unwary and fleece them,
typically with a false breakout.
The problem is that both sides are lazy. Those whose brains are wired in such a way
that working with numbers comes easily to them can’t be bothered to exert the modest
effort required to learn how to read stock charts. Those whose brains are more adept at
grasping things when presented in a graphic context won’t undertake the simple task of
learning how to play with numbers, for the same reason.
So what is one to do? The answer is simple. Choose the third path, that of reason.
Recognize that fundamental analysis and technical analysis co‐exist like bees and
honey. They compliment each other, and most importantly, if employed correctly,
confirm each other.
Profits by Timothy C Schewe