October 7, 2017 all-day
Oct 7, 1896. Dow Jones began reporting an average of the prices of 12 industrial stocks in the Wall Street Journal on this day. In the early years these were largely railroad stocks. In 1928 Mr Dow expanded the number of stocks to 30, where it currently remains. Today, the large, frequently traded stocks in the DJIA represent about a fifth of the market value of all US stocks.