Final answer:
Investors require a higher expected rate of return on common stock than on bonds because common stock is a riskier investment than bonds. The higher average return compensates for the higher degree of risk in stocks.
Step-by-step explanation:
Investors require a higher expected rate of return on common stock than on bonds because common stock is a riskier investment than bonds. Stocks have the potential for higher returns, but they also come with a higher degree of risk. On the other hand, bonds have a lower risk compared to stocks and therefore offer a lower expected rate of return. The higher average return compensates for the higher degree of risk in stocks, which is why investors demand a higher expected rate of return for common stock.