I'm no expert, but there are funds that are based on these composite indexes. Could mean AAPL gains more investors, for one. Second, AAPL's volatility may lessen as it becomes more widely held. This seems to me to be a very odd move by Dow Jones and it will be interesting to see how AAPL actually does influence the index. Perhaps a little more volatility is what they need since their composite growth versus Apple's growth has been dismal.