The Dow Industrials was expanded to 30 names from 20 on October 1 of 1928. Today, only nine names of the original 30 remain in the Dow. The committee at Dow Jones has replaced the other names as the companies grew out of favor, were merged into other stocks, were considered too small, or the committee felt that other companies better represented the industrial prowess of the US economy.
For instance, in November of 1999, Goodyear and Chevron were removed in order to allow Microsoft and Intel to join the Dow 30, where the two tech giants proceeded to rise handily the next few quarters. However, it has not been that pretty since the end of 2000, with both stocks down approximately 60% from their entry price, and much further from their peak price. Chevron proceeded to move up some 60% in price after it was removed, at which point Chevron was inserted back into the Dow 30 on February 19, 2008, where it is now down about 15%. Not a good run for the selection committee.
But it is not all bad. If you look at the deletions and additions, you find some interesting timing issues. Some additions were excellent in terms of performance. Some avoided later bankruptcies.
Basically the current crop is the best the commissioners could find for their basket. Add that to Clinton’s statistical invisible hand of everything is a-ok from BLS etc, and there isn’t any way to make historical comparrisons of any of the crap we currently use as economic guages, without jumping through hoops. I’ve got the time, but the guy watching tv after eight hours at work doesn’t.