A smart economist and blogger says something which probably reflects the approach of most ordinary investors:
http://www.arnoldkling.com/blog/ (permalink is broken)
"Speaking of stocks, I know of a newsletter writer who recommends specific stocks and always adds what he calls a âprotective stop.â So he might say, âbut X at 20, but put in a stop-less order to sell if it goes down to 18.â This struck me as a strange strategy, but today I was pondering it and I think I have it figured out.
Suppose that the stocks that he recommends are really no better or worse than buying an index fund. So, without the stop-loss orders, if you followed his buy recommendations you would get the exact same return as the market. With the stop-loss orders, itâs as if you are buying the market portfolio along with a portfolio of out-of-the-money put options. In this case, though, you only pay the option premium if the market bounces around, so you buy a stock at 20, sell it at 18, then buy it back (or buy some other stock recommended by the newsletter) when it goes back up to 20.
I think that this approach minimizes the chances that you will regret taking the writerâs advice. If the market rallies, you will be happy with your gains. If it falls, you will be happy that your losses are limited. And if it bounces up and down you are unlikely to notice that the advice is giving you a tendency to buy at the highs and sell at the lows. So I think this strategy would appeal to regret-averse investors. But itâs not a strategy that appeals to me."
Kling seems to think that losses are temporary, so any attempt to limit losses is irrational. He speaks of "regret-averse" instead of risk-averse because he doesn't really see a reason to limit losses, other than an irrational fear of regret.
If the auditor of HLF said to you, next quarter's earnings will be good, that would be a good bet to make. You might even leverage up. The problem is that even if you knew the destination, you wouldn't know the path. So there is an optimal strategy that isn't simply betting 1000% of your networth on HLF and waiting for the profits. Even if you knew the destination, it would make sense to use a stop loss.
Let's say you knew HLF would trade for $100 in 12 months. You are given these options,
a) buy now, but no opportunity to sell in the interim, and no leverage.
b) you can buy when you like, but no selling, and no leverage.
c) buy when you like, sell only once, and no leverage.
d) buy when you like, sell only once, and leverage.
e) no buying or selling restrictions, and no leverage.
f) no restrictions, leverage
Obviously, f is the best option. The value of f) simply illustrates the enormous option value of cash. But Kling prefers a), it seems. Or he thinks the selling options are limited to c) or d). But there is the possibility that the stock declines, post sale. Then the option of unlimited buys and sells is very valuable, versus a) thru d). Of course, if you don't know the price of HLF in 12 months, but you do have a high conviction about the price of the market in 20 years, then your best option might be a).