The Dow Jones Industrial Average closed at an all-time high on February 25, 2015, reaching 18,224.57, according to the International Business Times. The DJIA reached a record intraday trading high that day as well, reaching 18,244.38
The DJIA is the oldest and best-known market index in the world, according to The Motley Fool. Composed of 30 of America's largest companies, the DJIA is a broad representation of U.S. Industry. There are several companies that offer investment products, such as index funds and exchange traded funds, or ETFs, that track the performance of the DJIA. Because of the size of the companies that comprise the DJIA, and their importance in the American economy, the DJIA is relatively stable.