A classic Wall Street yarn, concerning a young man who was in the early stages of learning to be a professional speculator goes something like this. The young man had a problem, so he went to an elderly gentleman noted for his shrewd investment judgment, for advice. The young man had taken on quite an extensive line of stocks, but the market looked a bit over-valued and so he was thinking that his positions carried too many risks. He wondered if he shouldn’t perhaps sell. He was so worried about it that he was having trouble sleeping.
The old man’s advice was simple and direct: “Sell” he said. “Sell back to the sleeping point.” Although there is no doubt that this advice smacks of ambiguity, there is a simple wisdom in it. We may safely assume that neither the young man nor his elder adviser knew which way the market was going, but both were aware that the market was sufficiently shaky to cause legitimate worry. Translated into somewhat more orthodox investment terms, the advice meant – Sell enough of your stocks so that a market collapse won’t destroy you, but keep enough so that if your fears turn out to be groundless,...