The Dow Jones Industrial Average is an index comprising the average value of the stocks of 30 large corporations during a trading session. The Dow gives investors an idea of how well the entire stock market is doing and provides an assessment of the general health of the economy.
First calculated in 1896, the Dow Jones is the second-oldest market index. It initially included 12 companies, only one of which, General Electric, remains on the list in 2014. When it first opened, the index was at 62.76. After reaching a high of 381.17 in September of 1929, the Dow Jones dropped to the levels of its earliest years during the Great Depression. It topped 17,000 for the first time in July of 2014.