The Dow Jones Index is weighted by share price, not by company size. However, if we rank its 30 components by market capitalization, at the very bottom of the list we find four names that most investors do not immediately associate with the term “blue chip.” Each stock, however, has a different reason for finding itself at the bottom of the world’s most famous stock index.

The Dow Jones Industrial Average is the oldest and most closely watched U.S. stock index, but it operates on a principle that seems a bit archaic today. Unlike the S&P 500, where each company is weighted according to its market capitalization, the Dow is what’s known as a price-weighted index. This means that a specific company’s influence on the index’s movement is determined solely by the price of a single share, not by the company’s total value. A stock priced at $900 thus carries much greater weight in the index than a stock priced at $50, even if the cheaper one belongs to a significantly larger company.

If we…