TL;DR — the direct answer: The Nasdaq Composite fell 5.52% on Thursday 5 November 2026 — its worst day since the April 2025 tariff selloff — as investors dumped AI and chip stocks after the US midterm elections, wiping about $2.5 trillion in market value in a single session.
What happened: Wall Street had its worst session since early 2025 on Thursday 5 November 2026. The Nasdaq Composite dropped 5.52% to close at 24,315, the S&P 500 fell 4.33% to 7,356, and the Dow Jones Industrial Average plunged 3.44% — down 1,833 points to 51,523. The Nasdaq 100 fell 6.4%. The damage was concentrated exactly where the AI boom lives: the Philadelphia Semiconductor Index fell about 12%, which Reuters called its second-largest one-day fall on record. Nvidia dropped 9.26% to $181.60, losing almost $450 billion in market value in a single session, according to CNBC. AMD fell 17.26% and Micron roughly 17%, while Broadcom fell about 10%. The Nasdaq closed about 12% below the record it set on 6 October, putting it officially in correction territory. The reversal was sharp: only a day earlier, the Dow had jumped 1,569 points after the midterm results, its best day since April 2025.
Why it's trending: This is the sequel to the story this site covered a week ago, when Alphabet reportedly lost $500 billion in stock value on AI spending concerns. The question then was whether one company's fall was a warning about AI costs. Thursday's selloff suggests investors are now asking the same question about the whole sector at once. The two reasons most often cited in the day's reporting are politics and payback: first, the Democrats' midterm sweep raised expectations of tighter scrutiny of AI, possible limits on data-centre construction, and a slower, more expensive buildout; second, investors are questioning whether the enormous spending on AI data centres, chips and power will turn into profit fast enough to justify it. UBS analysts estimated that around 30% of expected US data-centre capacity additions in 2028 could face construction pauses, Reuters reported. None of this means demand for AI has fallen — the selloff is about the price investors are willing to pay for future growth, and how fast that growth arrives, not about people using AI less.
Background / context: The worry about AI spending predates the election. Reuters reported on 3 November that the Nasdaq-100 had already entered a correction as investors grew wary of Big Tech's AI spending with little evidence of adequate returns. Alphabet reported negative free cash flow of about $9.1 billion for the third quarter — its second straight negative quarter — on capital spending of $51.4 billion. Building and running modern AI systems is expensive in ways very different from building a website or an app: data centres full of specialised chips, enormous amounts of electricity and cooling, and large research teams, with constant investment needed because models improve only with more data and computing power. That creates the dilemma at the heart of this selloff. Spend too little and risk falling behind rivals; spend too much and risk cutting into profits for years before the investment pays off. Thursday's market punished the companies that build and finance AI capacity — chipmakers and data-centre builders — far harder than the big tech companies that own it: Meta fell about 4% while Nvidia lost about 9% and AMD about 17%.
What we know / what's unconfirmed: Confirmed across multiple market reports of the 5 November close: Nasdaq Composite down 5.52% to 24,315; S&P 500 down 4.33% to 7,356; Dow down 3.44% to 51,523; Nasdaq 100 down 6.4%; Philadelphia Semiconductor Index down about 12%; Nvidia down 9.26%; AMD down 17.26%. Estimates of the total market value wiped out range from about $2 trillion to about $2.5 trillion depending on the tally, so treat the $2.5 trillion figure as a reported estimate, not an exact count. The reasons for the fall — midterm-driven data-centre worries and doubts about AI spending returns — are the explanations given by analysts quoted in the day's coverage, not a proven single cause; markets rarely fall for one reason alone. Also unconfirmed: whether this is the start of a longer reassessment or a one-day move, and what Nvidia says next — it reports quarterly results on 17 November.
What happens next: The next big test is Nvidia's earnings on 17 November — its language on supply, power and customer timing will show whether AI orders are slipping or only the schedules. Investors will also watch whether any data-centre restrictions or AI regulation actually materialise after the midterms, and whether Big Tech's next results show AI spending levelling off or still climbing. For ordinary users, the practical effects are slower than the headline: AI features will not disappear because a share price fell, but pressure to show a return on AI investment may shape which features stay free, which move into paid plans, and how fast new ones arrive. Related reading: Alphabet Loses $500 Billion in Stock Value on AI Spending Concerns.
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Q: Did the Nasdaq really lose $2.5 trillion in a day?
A: About $2.5 trillion in market value was wiped out, according to reported estimates — market value is share price multiplied by shares in existence, so it is a paper loss in the total value of listed companies, not cash disappearing from bank accounts. Estimates range from about $2 trillion to $2.5 trillion depending on the tally.
Q: Why did AI stocks fall after the midterms?
A: Investors read the Democrats' midterm sweep as meaning the AI data-centre buildout could become slower and more expensive, with more scrutiny and possible construction limits — on top of existing doubts about whether huge AI spending will pay off quickly enough.
Q: Does this mean AI demand is falling?
A: Not according to the day's reporting. The selloff is about valuations and the timing of returns on AI infrastructure spending, not about people using AI less. Nvidia reports on 17 November, which will be the next real test.
Sources: Market close figures and reporting from Datafloq — Nasdaq Falls 5.5% as Investors Price In a Slower AI Buildout, Motley Fool — Stock Market Today, Nov. 5, and SKN Finance — Nasdaq Loses $2.5 Trillion, all 5–6 November 2026. Figures beyond those closes are presented as reported estimates, not independently verified.
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