The table below lists the total market capitalization of Dow Jones Industrial Average (DJIA) stock index. In 9/30/2018, the combined market value of all the companies part of the index was $7,494,441.10 million. The latest change to the index composition happened in June 26, 2018 when Walgreens Boots Alliance replaced General Electric.
[DJIA Index] – Total Market Cap
Purchase a dataset that lists the market caps of all current and past S&P 500 companies since 3/31/1979 and enterprise values since 3/31/1990. The market values are available for the last day of each quarter between 3/31/1979 and 12/31/2004 and for the last day of each month since 1/31/2005. Check a sample file from here.
The growth of Dow Jones companies during the past 45 years.
Between 1970 and 2015, the average yearly growth in the total market cap of Dow 30 index has been 9.9%. The decade with the fastest growth was 1990s but this include the excessive valuations before the dot-com boom. Between 2000 and 2009, the growth was negative 0.1%, mainly because of the financial crisis of 2000. The financial crisis decreased the value of the Dow Jones companies temporarily almost by half. The market values quickly recovered but there were casualties. The crisis dropped AIG and Citigroup from the index when Travelers and Cisco took their place. The values of the companies have steadily growing since 2008 but the growth began to halt during 2015 and 2016 started with large turbulence in stock markets around the world so the long bull market might be over.
Apple was the most valuable public US company at the time but was not added to the index until March 2015 when it replaced AT&T. Of the most valuable companies, both Alphabet (ex-Google) and Berkshire Hathaway are also missing from Dow. Instead of information technology, the largest sector of the index is financial companies.