Why does Morningstar return information for the S&P 500 not always match the index returns published elsewhere?
At Morningstar we assume reinvestment of dividends on the last day of the month for both mutual funds and indexes. This provides an apples-to-apples comparison between a fund’s total returns and the S&P 500 total returns of the S&P 500. Other sources do not assume reinvestment of dividends when calculating returns for the index. A note about the Standard & Poor’s 500 Index: The S&P 500 is a market-capitalization-weighted index of 500 widely held stocks often used as a proxy for the stock market. It measures the movement of the largest issues. Standard & Poor’s chooses the 500 companies that comprise the index based on market size, liquidity, and industry group representation. Included are the stocks of industrial, financial, utility, and transportation companies. For more information, visit the Standard & Poor’s Web site.
