Over 1999 and early 2000, the U.S. Federal Reserve had increased interest rates six times, and the economy was beginning to lose speed. The dot-com bubble burst, numerically, on March 10, 2000, when the technology heavy NASDAQ Composite index, peaked at 5,048.62 (intra-day peak 5,132.52), more than double its value just a year before. The NASDAQ fell slightly after that, but this was attributed to correction by most market analysts; the actual reversal and subsequent bear market may have been triggered by the adverse findings of fact in the United States v. Microsoft case which was being heard in federal court. The findings, which declared Microsoft a monopoly, were widely expected in the weeks before their release on April 3.
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One possible cause for the collapse of the NASDAQ (and all dotcoms that collapsed) was the massive, multi-billion dollar sell orders for major bellwether high tech stocks (Cisco, IBM, Dell, etc.) that happened by chance to be processed simultaneously on the Monday morning following the March 10 weekend. This selling resulted in the NASDAQ opening roughly four percentage points lower on Monday March 13 from 5,038 to 4,879—the greatest percentage 'pre-market' selloff for the entire year.
The massive initial batch of sell orders processed on Monday, March 13 triggered a chain reaction of selling that fed on itself as investors, funds, and institutions liquidated positions. In just six days the NASDAQ had lost nearly nine percent, falling from roughly 5,050 on March 10 to 4,580 on March 15.
Another reason may have been accelerated business spending in preparation for the Y2K switchover. Once New Year had passed without incident, businesses found themselves with all the equipment they needed for some time, and business spending quickly declined. This correlates quite closely to the peak of U.S. stock markets. The Dow Jones peaked on January 14, 2000 (closed at 11,722.98, with an intra-day peak of 11,750.28 and theoretical peak of 11,908.50) and the broader S&P 500 on March 24, 2000 (closed at 1,527.46, with an intra-day peak of 1,553.11); while, even more dramatically the UK's FTSE 100 Index peaked at 6,950.60 on the last day of trading in 1999 (December 30). Hiring freezes, layoffs, and consolidations followed in several industries, especially in the dot-com sector.
The bursting of the bubble may also have been related to the poor results of Internet retailers following the 1999 Christmas season. This was the first unequivocal and public evidence that the "Get Rich Quick" Internet strategy was flawed for most companies. These retailers' results were made public in March when annual and quarterly reports of public firms were released.
By 2001 the bubble was deflating at full speed. A majority of the dot-coms ceased trading after burning through their venture capital, many having never made a net profit. Investors often jokingly referred to these failed dot-coms as either "dot-bombs", "dot-compost" or "dot-shells".