Studies of correlations among monthly equity price index returns have found: Low correlations between various U.S. equity indexes High correlations between various U.S. equity indexes High correlations between U.S. and non-U.S. equity indexes Negative correlations between various U.S. equity indexes None of these Question 4 2.5 pts Which of the following are factors that make it difficult to create and maintain a bond index? The universe of bonds is broader than stocks. The universe of bonds is constantly changing due to new issues, bond maturities, calls, and bond sinking funds. It is difficult to derive value, up-to-date prices. Choices a and All of these