Historic $3 Trillion One-Day Loss in U.S. Stocks as Tech Shares Plunge Nasdaq Hits Worst Drop Since COVID - Thairath English

The U.S. stock market faced heavy sell-offs on Thursday, 5 Nov 2026 GMT+7, amid expectations that the Democratic Party might secure a significant victory in the U.S. midterm elections. This raised investor concerns, especially about tighter regulations and restrictions on Data Center construction, potentially impacting future AI infrastructure investments.

The sell-off spread across the market, particularly affecting technology stocks and companies in the AI supply chain. This caused the total market capitalization of S&P 500 companies to drop by about $3 trillion, or roughly 100 trillion baht, within a single day, wiping out gains from the previous day, which was the best market performance in three months.

The S&P 500 index fell 4.36%, its steepest decline since the Liberation Day tax crisis in April 2025, while the Dow Jones lost 1,833 points or 3.44%. The Nasdaq Composite plunged 5.52%, pushing the index into correction territory after dropping 11.9% from its all-time high reached in October.

The sell-off was not limited to U.S. markets but also impacted international stock markets. South Korea's Kospi index dropped 5.3%, Japan's stock market declined about 1.8%, and European and UK markets fell around 0.4%, reflecting pressure on risk assets amid concerns over the future of AI investments.

One indicator of the severity of the sell-off is the market capitalization loss of the "Magnificent Seven" tech stocks—Apple, Microsoft, Alphabet, Amazon, Nvidia, Meta, and Tesla—which collectively fell by more than $1 trillion, or approximately 33 trillion baht, in a single day.

Nvidia, the world’s leading AI chipmaker, was the hardest hit, with its stock price dropping about 9.3%, wiping out more than $440 billion, or roughly 14.7 trillion baht, of market value in one day.

This decline turned Nvidia's year-to-date 2026 returns negative 2.6%, after previously being one of the top-performing stocks benefiting from the AI investment surge in recent years.

Nvidia also exerted the greatest downward pressure on the S&P 500 index due to its very large market capitalization, where even small percentage changes in its share price significantly influence the overall index direction.

Other companies in the AI industry supply chain also faced heavy selling. Advanced Micro Devices (AMD), a chip and AI processor manufacturer, fell 17.3%, CoreWeave, a cloud-based AI compute provider, dropped 9.8%, and GE Vernova, an energy infrastructure supplier for Data Centers, declined 7.5%.

The damage extended beyond chip manufacturers to businesses benefiting from AI expansion, including cloud service providers, data storage systems, and the energy sector.

Looking at industry sector movements, all 11 sectors within the S&P 500 closed lower, indicating the sell-off was widespread and not limited to AI or large technology companies.

The Information Technology sector was hit hardest, falling 7.30%, marking its steepest single-day drop since 16 March 2020 during the COVID-19 crisis, when tech stocks fell as much as 13.92%. The Industrials sector fell 4.12%, its largest single-day decline since April 2025.

The Technology Select Sector SPDR Fund (XLK), which invests in large U.S. tech companies, dropped 8.04%, also recording its biggest daily decline since March 2020.

Of particular note is the Philadelphia Semiconductor Index (SOX), reflecting prices of major chip and semiconductor producers, which fell about 12%, marking the second-largest daily decline in its history.

Semiconductor companies suffered heavily, with SanDisk dropping around 22%, and Micron Technology, AMD, and Marvell Technology each falling about 17%.

This decline reflects investor concerns that if Data Center construction slows, demand for AI chips, memory, storage systems, and related devices may grow less than previously expected. The semiconductor industry, a direct beneficiary of massive AI investments, is among the first to face risk reduction as investment outlooks become uncertain.

A key factor behind the sell-off is the midterm election results on 6 November, where the Democratic Party is likely to win a significant victory and regain a majority in both houses of Congress. This has prompted investors to reassess risks related to U.S. economic and technology policies.

The AI industry, which has benefited from accelerated Data Center investments nationwide, faces opposition from residents in many areas concerned about energy use, water consumption, utility costs, and impacts on household electricity bills.

Reports indicate that in this election, 45 local proposals concerning Data Centers were on the ballot, with 39 aiming to limit AI infrastructure expansion receiving approval, signaling that Data Center issues are shifting from investment topics to political and cost-of-living concerns.

UBS analysts estimate that risks of suspending or delaying construction projects could affect about 30% of planned new Data Center capacity in the U.S. through 2028.. . .Although this figure represents only a risk assessment of potential capacity, it is enough to make investors question growth prospects of companies in the AI supply chain.

This shift also highlights an interesting market pattern: on Wednesday, investors reacted positively to election results, viewing changes in congressional power balance as a way to reduce policy uncertainty under the Trump administration.

But just one day later, the market began to weigh the potential negative impacts on the AI industry more heavily, particularly the likelihood of stricter regulations and construction limits on Data Centers.

However, the election outcome does not automatically mean AI investments will be halted, nor is it the sole reason for tech stock declines, as the market also faces concerns over higher financial costs and elevated earnings expectations for tech firms.

In recent months, the market has increasingly questioned the value of AI investments, especially for companies that have rapidly expanded processing capacity ahead of demand but still need to prove they can generate sufficient revenue and cash flow to justify the expenditures.

The key question going forward is whether AI-driven investment, a crucial driver of the U.S. economy, can sustain its growth momentum.

If many Data Center projects are delayed, impacts may ripple through orders for AI chips, storage devices, network systems, and energy consumption—all businesses benefiting from the recent AI boom.

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