The dot-com bubble (also known as the dot-com boom,  the tech bubble,  and the Internet bubble) was a stock market bubble caused by excessive speculation of Internet-related companies in the late 1990s, a period of massive growth in the use and adoption of the Internet.  
Between 1995 and its peak in March 2000, the Nasdaq Composite stock market index rose 400%, only to fall 78% from its peak by October 2002, giving up all its gains during the bubble. During the crash, many online shopping companies, such as Pets.com, Webvan, and Boo.com, as well as several communication companies, such as Worldcom, NorthPoint Communications, and Global Crossing, failed and shut down.   Some companies, such as Cisco, whose stock declined by 86%,  Amazon.com, and Qualcomm, lost a large portion of their market capitalization but survived.
The 1993 release of Mosaic and subsequent web browsers during the following years gave computer users access to the World Wide Web, popularizing use of the Internet.  Internet use increased as a result of the reduction of the " digital divide" and advances in connectivity, uses of the Internet, and computer education. Between 1990 and 1997, the percentage of households in the United States owning computers increased from 15% to 35% as computer ownership progressed from a luxury to a necessity.  This marked the shift to the Information Age, an economy based on information technology, and many new companies were founded.
At the same time, a decline in interest rates increased the availability of capital.  The Taxpayer Relief Act of 1997, which lowered the top marginal capital gains tax in the United States, also made people more willing to make more speculative investments.  Alan Greenspan, then- Chair of the Federal Reserve, allegedly fueled investments in the stock market by putting a positive spin on stock valuations.  The Telecommunications Act of 1996 was expected to result in many new technologies from which many people wanted to profit. 
As a result of these factors, many investors were eager to invest, at any valuation, in any dot-com company, especially if it had one of the Internet-related prefixes or a " .com" suffix in its name. Venture capital was easy to raise. Investment banks, which profited significantly from initial public offerings (IPO), fueled speculation and encouraged investment in technology.  A combination of rapidly increasing stock prices in the quaternary sector of the economy and confidence that the companies would turn future profits created an environment in which many investors were willing to overlook traditional metrics, such as the price–earnings ratio, and base confidence on technological advancements, leading to a stock market bubble.  Between 1995 and 2000, the Nasdaq Composite stock market index rose 400%. It reached a price–earnings ratio of 200, dwarfing the peak price–earnings ratio of 80 for the Japanese Nikkei 225 during the Japanese asset price bubble of 1991.  In 1999, shares of Qualcomm rose in value by 2,619%, 12 other large-cap stocks each rose over 1,000% in value, and seven additional large-cap stocks each rose over 900% in value. Even though the Nasdaq Composite rose 85.6% and the S&P 500 rose 19.5% in 1999, more stocks fell in value than rose in value as investors sold stocks in slower growing companies to invest in Internet stocks. 
An unprecedented amount of personal investing occurred during the boom and stories of people quitting their jobs to trade on the financial market were common.  The news media took advantage of the public's desire to invest in the stock market; an article[ which?] in The Wall Street Journal suggested that investors "re-think" the "quaint idea" of profits, and CNBC reported on the stock market with the same level of suspense as many networks provided to the broadcasting of sports events.  
At the height of the boom, it was possible for a promising dot-com company to become a public company via an IPO and raise a substantial amount of money even if it had never made a profit—or, in some cases, realized any material revenue. People who received employee stock options became instant paper millionaires when their companies executed IPOs; however, most employees were barred from selling shares immediately due to lock-up periods. [ page needed] The most successful entrepreneurs, such as Mark Cuban, sold their shares or entered into hedges to protect their gains. Sir John Templeton successfully shorted stocks at the peak of the bubble during what he called "temporary insanity" and a "once-in-a-lifetime opportunity", shorting stocks just before the expiration of lockup periods ending 6 months after initial public offerings.  
Most dot-com companies incurred net operating losses as they spent heavily on advertising and promotions to harness network effects to build market share or mind share as fast as possible, using the mottos "get big fast" and "get large or get lost". These companies offered their services or products for free or at a discount with the expectation that they could build enough brand awareness to charge profitable rates for their services in the future.  
The "growth over profits" mentality and the aura of " new economy" invincibility led some companies to engage in lavish spending on elaborate business facilities and luxury vacations for employees. Upon the launch of a new product or website, a company would organize an expensive event called a dot com party.  
The bubble in telecom was called "the biggest and fastest rise and fall in business history". 
Partially a result of greed and excessive optimism, especially about the growth of data traffic fueled by the rise of the Internet, in the five years after the Telecommunications Act of 1996 went into effect, telecommunications equipment companies invested more than $500 billion, mostly financed with debt, into laying fiber optic cable, adding new switches, and building wireless networks.  In many areas, such as the Dulles Technology Corridor in Virginia, governments funded technology infrastructure and created favorable business and tax law to encourage companies to expand.  The growth in capacity vastly outstripped the growth in demand.  Spectrum auctions for 3G in the United Kingdom in April 2000, led by Chancellor of the Exchequer Gordon Brown, raised £22.5 billion.  In Germany, in August 2000, the auctions raised £30 billion.   A 3G spectrum auction in the United States in 1999 had to be re-run when the winners defaulted on their bids of $4 billion. The re-auction netted 10% of the original sales prices.   When financing became hard to find as the bubble burst, the high debt ratios of these companies led to bankruptcy.  Bond investors recovered just over 20% of their investments.  However, several telecom executives sold stock before the crash including Philip Anschutz, who reaped $1.9 billion, Joseph Nacchio, who reaped $248 million, and Gary Winnick, who sold $748 million worth of shares. 
On January 31, 1999, two dot-com companies had purchased ad spots for Super Bowl XXXIII; that number increased to 17 the next year. 
Around the turn of the millennium, spending on technology was volatile as companies prepared for the Year 2000 problem.
There were concerns that computer systems would have trouble changing their clock and calendar systems from 1999 to 2000 which might trigger wider social or economic problems, but there was virtually no impact or disruption due to adequate preparation. 
On January 10, 2000, America Online, led by Steve Case and Ted Leonsis, announced a merger with Time Warner, led by Gerald M. Levin. The merger was the largest to date and was questioned by many analysts. 
On January 30, 2000, almost 20 percent [12 ads] of the 61 ads for Super Bowl XXXIV were purchased by dot-coms (however this estimate ranges from 12 to 19 companies depending on the source and the context in which the term "dot-com" company implies). At that time, the cost for a 30-second commercial cost between $1.9 million and $2.2 million.  
In 2000, Alan Greenspan, then Chair of the Federal Reserve, raised interest rates several times; these actions were believed by many to have caused the bursting of the dot-com bubble. According to Nobel laureate Paul Krugman, however, "he didn't raise interest rates to curb the market's enthusiasm; he didn't even seek to impose margin requirements on stock market investors. Instead, he waited until the bubble burst, as it did in 2000, then tried to clean up the mess afterward".  E. Ray Canterbery agrees with Krugman's criticism. 
On Friday March 10, 2000, the NASDAQ Composite stock market index peaked at 5,048.62. 
On March 15, 2000, Yahoo! and eBay ended merger talks and the Nasdaq fell 2.6%, but the S&P 500 rose 2.4% as investors shifted from strong performing technology stocks to poor performing established stocks. 
On March 20, 2000, Barron's featured a cover article titled "Burning Up; Warning: Internet companies are running out of cash—fast", which predicted the imminent bankruptcy of many Internet companies.  This led many people to rethink their investments. That same day, MicroStrategy announced a revenue restatement due to aggressive accounting practices. Its stock price, which had risen from $7 per share to as high as $333 per share in a year, fell $140 per share, or 62%, in a day.  The next day, the Federal Reserve raised interest rates, leading to an inverted yield curve, although stocks rallied temporarily. 
On April 3, 2000, judge Thomas Penfield Jackson issued his conclusions of law in the case of United States v. Microsoft Corp. (2001) and ruled that Microsoft was guilty of monopolization and tying in violation of the Sherman Antitrust Act. This led to a one-day 15% decline in the value of shares in Microsoft and a 350-point, or 8%, drop in the value of the Nasdaq. Many people saw the legal actions as bad for technology in general.  That same day, Bloomberg News published a widely read article that stated: "It's time, at last, to pay attention to the numbers". 
On Friday, April 14, 2000, the Nasdaq Composite index fell 9%, ending a week in which it fell 25%. Investors were forced to sell stocks ahead of Tax Day, the due date to pay taxes on gains realized in the previous year. 
By June 2000, dot-com companies were forced to re-evaluate their spending on advertising campaigns. 
On November 9, 2000, Pets.com, a much-hyped company that had backing from Amazon.com, went out of business only nine months after completing its IPO.   By that time, most Internet stocks had declined in value by 75% from their highs, wiping out $1.755 trillion in value. 
Investor confidence was further eroded by several accounting scandals and the resulting bankruptcies, including the Enron scandal in October 2001, the WorldCom scandal in June 2002,  and the Adelphia Communications Corporation scandal in July 2002. 
By the end of the stock market downturn of 2002, stocks had lost $5 trillion in market capitalization since the peak.  At its trough on October 9, 2002, the NASDAQ-100 had dropped to 1,114, down 78% from its peak.  
After venture capital was no longer available, the operational mentality of executives and investors completely changed. A dot-com company's lifespan was measured by its burn rate, the rate at which it spent its existing capital. Many dot-com companies ran out of capital and went through liquidation. Supporting industries, such as advertising and shipping, scaled back their operations as demand for services fell. However, many companies were able to endure the crash; 48% of dot-com companies survived through 2004, albeit at lower valuations. 
Several companies and their executives, including Bernard Ebbers, Jeffrey Skilling, and Kenneth Lay, were accused or convicted of fraud for misusing shareholders' money, and the U.S. Securities and Exchange Commission levied large fines against investment firms including Citigroup and Merrill Lynch for misleading investors. 
After suffering losses, retail investors transitioned their investment portfolios to more cautious positions.  Popular Internet forums that focused on high tech stocks, such as Silicon Investor, RagingBull.com, Yahoo! Finance, and The Motley Fool declined in use significantly. 
Layoffs of programmers resulted in a general glut in the job market. University enrollment for computer-related degrees dropped noticeably.   Anecdotes of unemployed programmers going back to school to become accountants or lawyers were common.
As growth in the technology sector stabilized, companies consolidated; some, such as Amazon.com, eBay, and Google gained market share and came to dominate their respective fields. The most valuable public companies are now generally in the technology sector.
In a 2015 book, venture capitalist Fred Wilson, who funded many dot-com companies and lost 90% of his net worth when the bubble burst, said about the dot-com bubble:
A friend of mine has a great line. He says "Nothing important has ever been built without irrational exuberance." Meaning that you need some of this mania to cause investors to open up their pocketbooks and finance the building of the railroads or the automobile or aerospace industry or whatever. And in this case, much of the capital invested was lost, but also much of it was invested in a very high throughput backbone for the Internet, and lots of software that works, and databases and server structure. All that stuff has allowed what we have today, which has changed all our lives... that's what all this speculative mania built. 
- Edwards, Jim (December 6, 2016). "One of the kings of the '90s dot-com bubble now faces 20 years in prison". Business Insider. Archived from the original on October 11, 2018. Retrieved October 11, 2018.
- "More Money Than Anyone Imagined". The Atlantic. July 26, 2019. Archived from the original on October 12, 2019. Retrieved February 10, 2020.
- "Here's Why The Dot Com Bubble Began And Why It Popped". Business Insider. December 15, 2010. Archived from the original on 2020-04-06.
- "The greatest defunct Web sites and dotcom disasters". CNET. June 5, 2008. Archived from the original on August 28, 2019. Retrieved February 10, 2020.
- Kumar, Rajesh (December 5, 2015). Valuation: Theories and Concepts. Elsevier. p. 25.
- Kline, Greg (April 20, 2003). "Mosaic started Web rush, Internet boom". The News-Gazette. Archived from the original on June 13, 2020. Retrieved February 10, 2020.
- "Issues in labor Statistics" (PDF). U.S. Department of Labor. 1999. Archived (PDF) from the original on 2017-05-12. Retrieved 2017-04-14.
- Weinberger, Matt (February 3, 2016). "If you're too young to remember the insanity of the dot-com bubble, check out these pictures". Business Insider. Archived from the original on March 13, 2020. Retrieved February 10, 2020.
- "Here's Why The Dot Com Bubble Began And Why It Popped". Business Insider. December 15, 2010. Archived from the original on April 6, 2020. Retrieved February 10, 2020.
- Teeter, Preston; Sandberg, Jorgen (2017). "Cracking the enigma of asset bubbles with narratives". Strategic Organization. 15 (1): 91–99. doi: 10.1177/1476127016629880.
- Litan, Robert E. (December 1, 2002). "The Telecommunications Crash: What To Do Now?". Brookings Institution. Archived from the original on March 30, 2018. Retrieved March 30, 2018.
- Smith, Andrew (2012). Totally Wired: On the Trail of the Great Dotcom Swindle. Bloomsbury Books. ISBN 978-1-84737-449-3. Archived from the original on 2020-08-01. Retrieved 2017-05-08.
- Norris, Floyd (January 3, 2000). "THE YEAR IN THE MARKETS; 1999: Extraordinary Winners and More Losers". The New York Times. Archived from the original on August 31, 2017. Retrieved August 26, 2017.
- Kadlec, Daniel (August 9, 1999). "Day Trading: It's a Brutal World". Time. Archived from the original on April 15, 2017. Retrieved April 14, 2017.
- Lowenstein, Roger (2004). Origins of the Crash: The Great Bubble and Its Undoing. Penguin Books. p. 115. ISBN 978-1-59420-003-8.
- Langlois, Shawn (May 9, 2019). "John Templeton profited from 'temporary insanity' in 2000 — now it's your turn, says longtime money manager". MarketWatch.
- "Old Dog, New Tricks". Forbes. May 28, 2001.
- BERLIN, LESLIE (November 21, 2008). "Lessons of Survival, From the Dot-Com Attic". The New York Times. Archived from the original on September 6, 2017. Retrieved August 26, 2017.
- Dodge, John (May 16, 2000). "MotherNature.com's CEO Defends Dot-Coms' Get-Big-Fast Strategy". The Wall Street Journal. Archived from the original on April 15, 2017. Retrieved April 14, 2017.
- Cave, Damien (April 25, 2000). "Dot-com party madness". Salon. Archived from the original on March 9, 2018. Retrieved March 8, 2018.
- HuffStutter, P.J. (December 25, 2000). "Dot-Com Parties Dry Up". Los Angeles Times. Archived from the original on June 13, 2020. Retrieved February 10, 2020.
- "The great telecoms crash". The Economist. July 18, 2002. Archived from the original on June 7, 2020. Retrieved June 7, 2020.
- Donnelly, Sally B.; Zagorin, Adam (August 14, 2000). "D.C. Dotcom". Time. Archived from the original on June 7, 2020. Retrieved February 10, 2020.
- "UK mobile phone auction nets billions". BBC News. April 27, 2000. Archived from the original on August 23, 2017. Retrieved June 7, 2020.
- Osborn, Andrew (November 17, 2000). "Consumers pay the price in 3G auction". The Guardian. Archived from the original on June 7, 2020. Retrieved June 7, 2020.
- "German phone auction ends". CNN. August 17, 2000. Archived from the original on June 7, 2020. Retrieved June 7, 2020.
- Keegan, Victor (April 13, 2000). "Dial-a-fortune". The Guardian. Archived from the original on February 5, 2021. Retrieved June 7, 2020.
- Sukumar, R. (April 11, 2012). "Policy lessons from the 3G failure". Mint. Archived from the original on June 7, 2020. Retrieved June 7, 2020.
- White, Dominic (December 30, 2002). "Telecoms crash 'like the South Sea Bubble'". The Daily Telegraph. Archived from the original on June 7, 2020. Retrieved June 7, 2020.
- Hunn, David; Eaton, Collin (September 12, 2016). "Oil bust on par with telecom crash of dot-com era". Houston Chronicle. Archived from the original on June 7, 2020. Retrieved June 7, 2020.
- "Inside the Telecom Game". Bloomberg Businessweek. August 5, 2002. Archived from the original on 2020-06-07. Retrieved 2020-06-07.
- Beer, Jeff (2020-01-20). "20 years ago, the dot-coms took over the Super Bowl". Fast Company. Archived from the original on 2020-03-02. Retrieved 2020-03-02.
- Marsha Walton; Miles O'Brien (1 January 2000). "Preparation pays off; world reports only tiny Y2K glitches". CNN. Archived from the original on 7 December 2004.
- Johnson, Tom (January 10, 2000). "Thats AOL folks". CNN. Archived from the original on December 11, 2017. Retrieved October 29, 2018.
- Pender, Kathleen (September 13, 2000). "Dot-Com Super Bowl Advertisers Fumble / But Down Under, LifeMinders.com may win at Olympics". San Francisco Chronicle. Archived from the original on March 2, 2020. Retrieved March 2, 2020.
- Kircher, Madison Malone (February 3, 2019). "Revisiting the Ads From 2000's 'Dot-Com Super Bowl'". New York. Archived from the original on March 2, 2020. Retrieved March 2, 2020.
- Krugman, Paul (2009). The Return of Depression Economics and the Crisis of 2008. W.W. Norton. p. 142. ISBN 978-0-393-33780-8.
- Canterbery, E. Ray (2013). The Global Great Recession. World Scientific. pp. 123–135. ISBN 978-981-4322-76-8.
- Long, Tony (March 10, 2010). "March 10, 2000: Pop Goes the Nasdaq!". Wired. Archived from the original on March 8, 2018. Retrieved March 8, 2018.
- "Nasdaq tumbles on Japan". CNN. March 13, 2000. Archived from the original on October 30, 2018. Retrieved October 29, 2018.
- "Dow wows Wall Street". CNN. March 15, 2000. Archived from the original on October 30, 2018. Retrieved October 29, 2018.
- Willoughby, Jack (March 10, 2010). "Burning Up; Warning: Internet companies are running out of cash—fast". Barron's. Archived from the original on March 30, 2018. Retrieved March 30, 2018.
- "MicroStrategy plummets". CNN. March 20, 2000. Archived from the original on October 11, 2018. Retrieved October 29, 2018.
- "Wall St.: What rate hike?". CNN. March 21, 2000. Archived from the original on October 11, 2018. Retrieved October 29, 2018.
- "Nasdaq sinks 350 points". CNN. April 3, 2000. Archived from the original on August 11, 2018. Retrieved October 29, 2018.
- Yang, Catherine (April 3, 2000). "Commentary: Earth To Dot Com Accountants". Bloomberg News. Archived from the original on 2017-05-25. Retrieved 2017-05-04.
- "Bleak Friday on Wall Street". CNN. April 14, 2000. Archived from the original on November 27, 2020. Retrieved February 10, 2020.
- Owens, Jennifer (June 19, 2000). "IQ News: Dot-Coms Re-Evaluate Ad Spending Habits". AdWeek. Archived from the original on May 25, 2017.
- "Pets.com at its tail end". CNN. November 7, 2000. Archived from the original on July 27, 2018. Retrieved October 29, 2018.
- "The Pets.com Phenomenon". MSNBC. October 19, 2016. Archived from the original on June 12, 2018. Retrieved June 28, 2018.
- Kleinbard, David (November 9, 2000). "The $1.7 trillion dot.com lesson". CNN. Archived from the original on October 24, 2018. Retrieved October 29, 2018.
- Elliott, Stuart (January 8, 2001). "In Super Commercial Bowl XXXV, the not-coms are beating the dot-coms". The New York Times. Archived from the original on August 31, 2017. Retrieved August 26, 2017.
- "World markets shatter". CNN. September 11, 2001. Archived from the original on September 20, 2020. Retrieved February 10, 2020.
- Beltran, Luisa (July 22, 2002). "WorldCom files largest bankruptcy ever". CNN. Archived from the original on October 30, 2018. Retrieved October 29, 2018.
- "SEC Charges Adelphia and Rigas Family With Massive Financial Fraud". www.sec.gov. Retrieved 2021-04-18.
- Gaither, Chris; Chmielewski, Dawn C. (July 16, 2006). "Fears of Dot-Com Crash, Version 2.0". Los Angeles Times. Archived from the original on December 18, 2019. Retrieved February 10, 2020.
- Glassman, James K. (February 11, 2015). "3 Lessons for Investors From the Tech Bubble". Kiplinger's Personal Finance. Archived from the original on 2020-04-04. Retrieved 2020-02-10.
- Alden, Chris (March 10, 2005). "Looking back on the crash". The Guardian. Archived from the original on January 4, 2018. Retrieved March 30, 2018.
- "Ex-WorldCom CEO Ebbers found guilty on all counts - Mar. 15, 2005". CNN. Retrieved 2021-06-20.
- Reuteman, Rob (August 9, 2010). "Hard Times Investing: For Some, Cash Is Everything And Only Thing". CNBC. Archived from the original on May 25, 2017. Retrieved September 9, 2017.
- Forster, Stacy (January 31, 2001). "Raging Bull Goes for a Bargain As Interest in Stock Chat Wanes". The Wall Street Journal. Archived from the original on December 9, 2018. Retrieved December 9, 2018.
- desJardins, Marie (October 22, 2015). "The real reason U.S. students lag behind in computer science". Fortune. Archived from the original on March 7, 2020. Retrieved February 10, 2020.
- Mann, Amar; Nunes, Tony (2009). "After the Dot-Com Bubble: Silicon Valley High-Tech Employment And Wages in 2001 and 2008". Bureau of Labor Statistics. Archived from the original on 2018-11-16. Retrieved 2017-04-14.
- Kennedy, Brian (September 15, 2006). "Remembering the Dot-Com Throne". New York. Archived from the original on June 6, 2020. Retrieved February 10, 2020.
- Donnelly, Jacob (February 14, 2016). "Here's what the future of bitcoin looks like—and it's bright". VentureBeat. Archived from the original on April 15, 2017. Retrieved April 14, 2017.
- Abramson, Bruce (2005). Digital Phoenix; Why the Information Economy Collapsed and How it Will Rise Again. MIT Press. ISBN 978-0-262-51196-4.
- Aharon, David Y.; Gavious, Ilanit; Yosef, Rami (2010). "Stock market bubble effects on mergers and acquisitions". The Quarterly Review of Economics and Finance. 50 (4): 456–70. doi: 10.1016/j.qref.2010.05.002.
- Cassidy, John (2009). Dot.con: How America Lost Its Mind and Its Money in the Internet Era. Harper Collins. ISBN 9780061841781.
- Cellan-Jones, Rory (2001). Dot.Bomb: The Rise and Fall of Dot.com Britain. Aurum. ISBN 978-1854107909.
- Daisey, Mike (2014). Twenty-one Dog Years: Doing Time at Amazon.com. Free Press. ISBN 978-0-7432-2580-9.
- Goldfarb, Brent D.; Kirsch, David; Miller, David A. (April 24, 2006). "Was There Too Little Entry During the Dot Com Era?". Robert H. Smith School Research Paper (RHS 06-029). SSRN 899100.
- Kindleberger, Charles P. (2005). Manias, Panics, and Crashes: A History of Financial Crises. John Wiley & Sons. ISBN 9780230365353.
- Kuo, David (2001). dot.bomb: My Days and Nights at an Internet Goliath. ISBN 978-0-316-60005-7.
- Lowenstein, Roger (2004). Origins of the Crash: The Great Bubble and Its Undoing. Penguin Books. ISBN 978-1-59420-003-8.
- Wolff, Michael (1999). Burn Rate: How I Survived the Gold Rush Years on the Internet. Orion Publishing Group. ISBN 9780752826066. Burn Rate at Google Books.