From Margin of Safety:
…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% annual returns over a decade, for example, will, perhaps surprisingly, end up with more money than an investor who earns 20% a year for nine years and then loses 15% the tenth year.
There is an understandable, albeit uneconomic, appeal to the latter pattern of returns, however. The second investor will outperform the former nine years out of ten, gaining considerable psychic income from this apparently superior performance. If both investors are money management professionals, the latter may also have a happier clientele (90% of the time, they will be doing better) and thus a more successful company. This may help to explain why risk avoidance is not the primary focus of most institutional investors.