The Dot Com Crash occured from March to October in 2002 -- when the NASDAQ stock market composite index lost 78% of its value. The bubble began in the mid 1990s with widespread, public availability of the World Wide Web.
The new economy of the Internet set the stage for euphoria where speculators were barely able to control their excitement. The crash was set into motion as a series of losses and failures (such as Netscape) were reported in the first quarter of 2000.