The Dow Jones Index was developed by Charles Doe, founder of the Dow Jones Company and publisher of The Wall Street Journal.
For the first time, the Dow Jones indicator was calculated in 1884 for the shares of 11 companies: 9 railroad and 2 industrial. Later, this index changed, but the basis for its calculation was always the shares of transport companies. This index still exists today, and since 1970 it has been called the Dow Jones Transportation Average. Currently, the transport index is calculated for the shares of the 20 largest transport companies in the United States.
The Dow Jones Industrial Average (or, as we defined, the Dow Jones average) was first calculated in 1896 for the shares of 12 industrial companies, and it was this index that evolved today into the widely known Dow Jones Industrial Average (DJIA). in 3 1928 and to this day, this figure covers 30 high-class industrial companies in the United States, whose stock performance is considered representative of the overall dynamics of the securities market. The shares of these companies are called blue chips.
The list of companies for the DJIA determination is revised from time to time. These or those shares leave the stock market due to the merger of companies, or the loss of some of them activity in the market or due to their bankruptcy. In such cases, the calculation includes shares of other companies, that is, the index as a whole is adjusted so that it can be compared with the previous indicator. For this, a special coefficient is used.