New York: Wall Street suffered its steepest single-day decline in 19 months on Thursday, November 5, as a sharp sell-off in technology and artificial intelligence (AI)-linked shares wiped out the optimism generated by the previous session’s post-midterm election rally.

The Nasdaq Composite plunged 5.5% to close at 24,315, while the S&P 500 fell 4.4% to 7,353.73. The Dow Jones Industrial Average dropped 1,833 points, or 3.4%, to 51,523.06. The losses marked the worst daily performances for the major US indices since the market turmoil triggered by President Donald Trump’s tariff announcement in April 2025.

The dramatic reversal came just a day after US stocks had rallied following the Democrats’ strong performance in the midterm elections. Investors initially welcomed the election outcome, viewing it as a possible check on the Trump administration. However, attention quickly shifted to what Democratic gains could mean for technology policy, AI investment and the construction of large data centres.

One-day rally erased by heavy selling

The sharp fall on Thursday reversed much of the market’s gains from Wednesday, when investors celebrated the Democrats’ sweeping election victories.

The Dow had climbed more than 1,500 points in the previous session, while technology shares also advanced as investors assessed the potential impact of the election results on the balance of political power in Washington.

That optimism did not last. On Thursday, traders shifted their focus from the immediate political outcome to the possibility that a stronger Democratic presence in Congress and state governments could bring tighter oversight of the technology industry.

The Nasdaq was particularly vulnerable because of its heavy exposure to semiconductor manufacturers, AI developers and technology companies. Selling intensified as investors reassessed the valuations of businesses that have benefited from the enormous spending on AI infrastructure.

AI data centre restrictions trigger investor concerns

One of the major concerns behind the sell-off was the possibility of restrictions on new data centre projects.

Data centres are essential to the development and operation of advanced AI systems. They house the powerful processors and servers needed to train AI models and provide computing capacity to businesses and consumers.

However, their rapid expansion has raised concerns about electricity consumption, water usage, pressure on local power networks and the impact on communities. Opposition to large data centre developments has grown in several parts of the United States.

Democratic victories in important state-level contests have prompted investors to consider whether new administrations could introduce stricter approval procedures, impose local restrictions or delay construction projects.

Texas attracted particular attention because of its importance to the planned expansion of data centre capacity. The state’s incoming Democratic governor, Gina Hinojosa, has pledged to halt new data centre projects, adding to concerns among companies and investors that political opposition could slow infrastructure development.

At the federal level, Democrats have also proposed measures relating to electricity costs for consumers and independent testing of AI systems. These proposals have contributed to uncertainty over the regulatory environment facing technology companies.

Semiconductor stocks lead the market decline

Technology and semiconductor companies were among the worst performers during Thursday’s trading session.

The Philadelphia Semiconductor Index dropped approximately 12%, reflecting heavy selling across chip manufacturers and suppliers of AI computing infrastructure.

Nvidia, one of the biggest beneficiaries of the AI boom, fell sharply. Other companies exposed to memory chips, processors and data storage also recorded steep losses.

Micron Technology and Advanced Micro Devices (AMD) declined by around 16% in reports tracking the day’s market movements. SanDisk and Western Digital also suffered substantial falls as investors reduced exposure to companies associated with the AI data centre expansion cycle.

The weakness was not restricted to chipmakers. Companies involved in cloud computing, data centre development and related technology services also came under pressure.

The broad-based selling indicates that investors were reassessing the entire AI investment ecosystem, rather than reacting to developments at a single company.

Nasdaq enters correction territory

The Nasdaq’s 5.5% decline pushed the index into correction territory, generally defined as a fall of at least 10% from a recent peak.

The index had been under pressure as investors questioned whether the rapid rise in AI-related valuations could be sustained. Thursday’s decline deepened those concerns and erased the gains made during the previous session.

The S&P 500 also recorded its steepest daily fall since April 2025. The Dow’s decline of 1,833 points reflected the spread of selling beyond technology shares.

The Russell 2000, which tracks smaller US companies, also fell 4.4% to 2,729.89. This suggested that the market weakness was not limited to the largest technology businesses.

Despite the losses, all four major indices remained higher for the year, according to Associated Press market data. However, the scale of Thursday’s decline showed how quickly investor sentiment can change when political and economic uncertainties affect heavily valued sectors.

Market volatility rises as investors reduce risk

The sell-off also reflected a wider shift towards caution among investors. The Cboe Volatility Index, commonly known as Wall Street’s fear gauge, rose sharply as demand for protection against further market declines increased.

Analysts attributed the pressure to a combination of factors, including profit-taking after Wednesday’s rally, concerns about the future of AI infrastructure spending and uncertainty over the political consequences of the election results.

Technology stocks had attracted significant investment during the AI boom, with investors betting that demand for computing power would continue to rise. However, high valuations leave these companies vulnerable when expectations change.

The market is now weighing whether the costs of building AI infrastructure can be justified by the revenue and profits that these investments are expected to generate.

If data centre projects face delays or additional regulatory requirements, companies supplying chips, servers and related equipment could experience slower growth than investors had anticipated.

What the Wall Street sell-off means for Indian investors

The sharp decline in US markets can influence global investor sentiment, particularly because major American technology companies have a significant presence in international equity indices and investment portfolios.

Indian investors holding US stocks, international mutual funds or exchange-traded funds with exposure to American technology companies may see the impact of the correction reflected in their investments.

However, a fall in Wall Street indices does not automatically mean that Indian markets will follow the same direction. Domestic share prices are also influenced by Indian corporate earnings, economic growth, interest rates, foreign institutional investment and developments in individual sectors.

Investors should therefore avoid making decisions based solely on a single session’s movement in US markets. The impact on Indian portfolios will depend on the extent of their exposure to the affected companies and the duration of the global technology correction.

AI investment faces a fresh test

Thursday’s market decline exposed the uncertainty surrounding one of Wall Street’s biggest investment themes. While artificial intelligence continues to attract significant spending, investors are increasingly examining the costs, regulatory risks and potential returns associated with the sector.

The Democrats’ election victories have added a political dimension to those concerns, particularly around data centre construction and the infrastructure needed to support AI development.

The immediate question for markets is whether Thursday’s sell-off represents a short-term correction following an unusually strong rally or the beginning of a more sustained reassessment of technology valuations.

For now, investors are likely to monitor policy signals, corporate investment plans and upcoming financial results closely. The sharp reversal serves as a reminder that even the strongest market rallies can quickly lose momentum when expectations and risk assessments change.