During the 2000–2002 dot-com crash, the Nasdaq Composite lost about 78% from peak to trough.
The index reached a record closing level of 5,048.62 on March 10, 2000. It then fell as investors reassessed internet companies whose share prices had often been justified by rapid user growth rather than profits, cash flow, or sustainable business models.
The Nasdaq Composite eventually reached a closing low of 1,114.11 on October 9, 2002. That was a decline of roughly 78% from its 2000 peak. The index was especially exposed because it contained many technology and communications companies.
The S&P 500 and Dow Jones Industrial Average also declined during this period, but neither matched the Nasdaq Composite's percentage loss. The crash did not mean that every internet company failed; firms with durable businesses, including Amazon, survived and later expanded.