The Dow Jones Industrial Average (^DJI 0.97%) is a price-weighted index that tracks 30 U.S. companies. While inclusion is not based on strict rules, the index committee tends to select stocks that have three qualities: an excellent reputation, sustained growth, and widespread interest among investors.On Nov. 8, semiconductor company Nvidia (NVDA -3.22%) did something it has never done before: It joined the Dow Jones Industrial Average. Sherwin-Williams was added to the index at the same time, while chipmake ...