The U.S. technology-heavy stock index that fell sharply after the dot-com bubble peaked in March 2000 was the Nasdaq Composite.
The Nasdaq Composite reached a closing peak of 5,048.62 on 10 March 2000. It then declined as investors reassessed internet and technology companies whose prices had been driven by expectations of rapid growth. Many firms had little revenue or no profits, yet their shares traded at extraordinary valuations.
The decline became a defining part of the dot-com crash. By October 2002, the Nasdaq Composite had lost roughly 78% from its peak. The downturn affected venture capital, technology employment, telecommunications investment, and many publicly traded internet companies.
The Nasdaq Composite includes thousands of common stocks listed on the Nasdaq market, so it is not limited strictly to internet companies. The Nasdaq-100 is a different index, containing 100 large non-financial Nasdaq-listed companies. Confusing those two indexes is a frequent error.