A key implication of the Efficient Market Hypothesis is that ... O Since security prices are random, random portfolio selection is just as good as any other method. Since prices are efficient, you will not be compensated for risk. You cannot earn an above-average return by investing in the stock market. If your portfolio earns more than it should based on its level of risk, it is just a matter of luck. News events occur in a predictable fashion and are already included in the prices of stocks