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.

When the Dow Jones was officially incepted on May 26, 1896, it was comprised of a dozen companies, most of which were tied to the industrial sector. Today, it contains an assortment of 30 historically profitable, time-tested, industry-leading businesses.