The S&P 500 and the Dow Jones Industrial Average indices are proxies for the broader US stock market. You notice one day that the S&P 500 closed UP by 0.20%, while the DJIA closed DOWN by 0.20%.

Explain how it is possible for one proxy (S&P 500) to have a positive return while the other (DJIA) has a negative return on any given day. Include in your explanation some of the names that could have caused this discrepancy. Which return (S&P 500 or DJIA) is more indicative of the 'true market return'?

To facilitate your analysis, the components of the S&P 500 and DJIA. Hint: Recall the S&P 500 contains the largest 500 US companies where the weight of each name is proportional to its market value. The DJIA is a price-weighted index comprised of select 30 names representing certain industries.