Risk avoidance is the single most important element of an investment program

Another common belief is that risk avoidance is incompatible with investment success. This view holds that high return is attainable only by incurring high risk and that long-term investment success is attainable only by seeking out and bearing, rather than avoiding, risk. Why do I believe, conversely, that risk avoidance is the single most important element of an investment program? 

If you had $1,000, would you be willing to wager it, double or nothing, on a fair coin toss? Probably not.  Would you risk your entire net worth on such a gamble? Of course not. Would you risk the loss of, say, 30 percent of your net worth for an equivalent gain? Not many people would because the loss of a substantial amount of money could impair their standard of living while a comparable gain might not improve it commensurately. If you are one of the vast majority of investors who are risk averse, then loss avoidance must be the cornerstone of your investment philosophy.

Greedy, short-term-oriented investors may lose sight of a sound mathematical reason for avoiding loss: the effects of compounding even moderate returns over many years are compelling, if not downright mind boggling.

Perseverance at even relatively modest rates of return is of the utmost importance in compounding
your net worth. A corollary to the importance of compounding is that it is very difficult to recover from even one large loss, which could literally destroy all at once the beneficial effects of many years of investment success. In other words, an investor is more likely to do well by achieving consistently good returns with limited downside risk than by achieving volatile and sometimes even spectacular gains but with considerable risk of principal An investor who earns 16 percent annual returns over a decade, for example, will, perhaps surprisingly, end up with more money than an investor who earns 20 percent a year for nine years and then loses 15 percent the tenth year.