Hence, the fact the decline may occur does not mean that he is running a true risk or loss.
If a group of well-selected common stock investment shows a satisfactory overall return as measured through a fair number of years then this group of investment has proved to be safe.
During that period, its market value was bound to fluctuate and likely than not, would sell for a while under the buyer's cost.
If that fall makes the investment risky, it would then have to be called both risky and safe at the same time.
This confusion may be avoided if we apply the concept of risk solely to a loss in value which:
- either is realized through an actual sale
- or is caused by significant deterioration in the company's position
- or more frequently, perhaps is the result of paying an excessive price in relation to the intrinsic worth of the security.
Many common stocks involve risks of such deterioration but it is our thesis that a properly executed group of investment in common stocks does not carry any substantial risk of this sort.
Ref: Intelligent Investor by Benjamin Graham
It is conventional to speak of good bonds as less risky than good preferred and that the latter as less risky than good common stocks.
From this was derived the popular prejudice against common stocks because they are not safe but we believe that what is here involved is not a true risk in the useful sense of the term.
If an investor's list has been competently selected in the first instance, there should be no need for frequent or numerous changes to the portfolio.