Aside from the considerations we discussed last week, there is this to remember about stock performance, the performance of a stock as an investment is not (entirely) a matter of whether it rises or falls in price. A stock also entitles its holder to a portion of whatever dividends the issuing company may declare. Suppose, then, that we do the arithmetical magic to factor in the dividend stream as if it were being paid out day by day, and we included that along with the stock price move as the performance of XYZ. Once we do this, we’ll want to be sure that we’re matching the stock price against a broad market benchmark that also includes dividends as part of performance.
Fortunately, these are readily available.
The S&P Index, for example, comes in three variants: one that considers
solely the price of component stocks; one that factors in dividends (the “total
return” index); and a third that subtracts the tax on those dividends (“net
return.”)
We might make discussion easier by
giving a name to the difference between the stock performance figure for a particular stock (or of your personal portfolio of stocks) on the one hand, and of the
broad market’s equivalent on the other. Let us call this difference alpha.
Positive alpha is a good thing. It means you're doing better than 'the house.' Negative alpha means you're doing worse.
Positive alpha is a good thing. It means you're doing better than 'the house.' Negative alpha means you're doing worse.
Now: a curve for a particular
stock’s alpha as we’ve defined it will often look a lot like the Bell curve.
One significant implication of this: alpha nets out to zero. That is worth saying again: alpha nets out to zero. In graphical terms, there is as much
space beneath the left-hand (negative alpha) side of the pertinent bell curve as there is
beneath the right-hand (positive alpha) side of the curve.
This is a good moment to observe
that stock picking, betting your nest egg on the future of individual stocks,
or on some expensive “active manager's” ability to buy individual stocks, is
usually a bad idea. It is cheaper and safer to invest indirectly through broad
based (passively managed) funds or exchange traded funds (ETFs). It is best to bet on that index against which
alpha is measured, rather than betting on some stock’s alpha itself. Why? Because (a) have I mentioned this yet? alpha nets out to zero and
(b) if you're trying to beat the market, you're paying a broker and/or advisers for that zero.
Let us ask another sort of question now. If stock price moves are random
(or to the extent that they are): why are they random?
One widespread view is that stock
prices jump about in a “random walk” fashion precisely because the stock market
is accomplishing its job. This is also, with important qualifications, my own view: the market is a venue for the efficient allocation of
capital, according to rational expectations, and the randomness arises from that fact. This is a somewhat counter-intuitive idea. After all, in most contexts
in our day-to-day life randomness is a bad thing. When I get up in the morning
and get into my car for the drive to work and turn the key in the ignition, I
want the car to start. Deterministically. Certainly. I don’t want there to be
any uncertainty or randomness about it!
But the stock markets are a rather
different sort of mechanism. Or, rather, they aren’t a sort of mechanism at all, but a
meeting place for a lot of different vitalisms. And in this context, it might
help us to consider a simple seasonal development, like the arrival of
Halloween. Presumably in parts of the world where Halloween is celebrated, the
demand for pumpkins rises rather suddenly every October and falls even more
suddenly at the end of that month.
“Aha!” says the naïve investor, “so
I can get rich! All I have to do is find a way to bet all my money and all the money
I can borrow on the prospect that pumpkins will rise in price this coming
October. My bet will pay off, and I’ll be rolling in enough dough to take full
advantage of the big cranberry crunch the following month.”
Sorry, that doesn’t work. If you
voice such a speculation out loud, your neighbor surely says, “if it were that
easy, everyone would do it.” And he’s right. Think of the market as a
collective intelligence: Mr. Market. Now, surely, Mr. Market knows that people
are going to want to buy pumpkins by late October and are going to want cranberries
by late November. The prices of these products and all derivatives of those
prices factor in such matters. So, sorry, you don’t get to outsmart Mr. Market
that way.
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