Most indexes, like the S&P 500 and Nasdaq Composite, assign a higher weighting to the largest companies by market cap. For example, Apple has roughly 11 times the market cap of Coca-Cola, so it has a much higher weighting in the S&P 500. But in the Dow, Apple is the 12th highest-weighted company by market cap because the index is price-weighted.

The ins and outs of membership in the 30-company group that represents success across industries and reflects stock market conditions.

Intel will be replaced by Nvidia in the Dow Jones industrial average after a 25 year run, signaling a shift in the semiconductor industry.