New York (AFP) - Wall Street stocks tumbled Thursday as the market fixated on worries that this week’s US midterm election results could slow or derail the artificial intelligence data center investment boom.

After initially cheering Tuesday’s Democratic drubbing of Donald Trump’s Republican Party, investors adopted a more anxious posture centered on worries that the electoral shakeup will hit key AI investments seen as important to economic growth.

Of the major US indices, the most impacted was the tech-focused Nasdaq, which finished down 5.5 percent at 24,315.00, losing more than 1,400 points in a sell-off that battered Nvidia and other semiconductor stocks.

It was the Nasdaq’s worst session in terms of percentage loss since April 2025.

“When there’s a concern about the capital spending at AI data centers, the market has a pretty violent reaction to that,” said Art Hogan of B. Riley Wealth Management.

Data centers have faced broad opposition from US voters regardless of political affiliation, and many midterm winners have pledged to put the brakes on such projects.

Hogan cited as a catalyst a call on social media late Wednesday from progressive US Senator Bernie Sanders for a national data center moratorium.

Hogan noted that key decisions on data centers come at the state and local level, but said the Sanders statement dented sentiment.

US stocks began the day mixed, but investor mood darkened soon after the opening bell and never recovered. A rebound in oil prices also dampened sentiment in equities trading.

Briefing.com analyst Patrick O’Hare said investors were also rattled by the quick reversal in market sentiment.

“You had a market that was feeling pretty good about things yesterday. And less than a day later, everything’s been turned around,” O’Hare said.

“So price action like that leaves a lot of market participants reluctant to chase after the stocks that have sold off because they’re worried about incurring further losses.”

- Oil prices rebound -

Oil prices recovered after plunging as much as 10 percent Wednesday on hopes of progress towards ending the US-Iran war, should increased Democratic pressure lead towards a diplomatic solution.

“A release valve has been unscrewed following the Democratic success of the midterms, with pent-up concerns about an escalation of the war in the Middle East evaporating,” said Susannah Streeter, chief investment strategist at Wealth Club.

European stocks initially rose on relief following the US midterm election results, with Frankfurt’s DAX index hitting a record high and London coming close to a new all-time peak.

But both ended the day in the red.

Tech-heavy Asian stock markets slid overall, with Seoul, the poster child of the AI-led surge in the first half of 2026, shedding more than five percent.

In Britain, the pound was little changed after the Bank of England raised its benchmark interest rate, as expected, for the first time in more than three years as inflation remains elevated.

Away from AI and Trump, shares in Air France-KLM climbed nearly 13 percent after the carrier surprised investors with higher operating profit in the third quarter despite a soaring jet fuel bill.

Rheinmetall plunged more than 15 percent as the German defense giant cut its earnings outlook for a second time in several months after Berlin pulled the plug on a major warship contract.

- Key figures at around 2025 GMT -

New York - Dow: DOWN 3.4 percent at 51,523.06 (close)

New York - S&P 500: DOWN 4.4 percent at 7,353.73 (close)

New York - Nasdaq Composite: DOWN 5.5 percent at 24,315.00 (close)

London - FTSE 100: DOWN 0.4 percent at 10,782.66 (close)

Paris - CAC 40: UP 0.3 percent at 8,205.86 (close)

Frankfurt - DAX: DOWN 0.4 percent at 26,325.01 (close)

Tokyo - Nikkei 225: DOWN 1.8 percent at 61,077.90 (close)

Hong Kong - Hang Seng Index: UP 3.7 percent at 24,796.98 (close)

Shanghai - Composite: UP 0.1 percent at 3,689.91 (close)

Brent North Sea crude: UP 3.9 percent at $98.29 per barrel

West Texas Intermediate: UP 2.7 percent at $90.52 per barrel

Euro/dollar: DOWN at $1.1222 from $1.1228 on Wednesday

Pound/dollar: DOWN at $1.3454 from $1.3471

Dollar/yen: DOWN at 157.83 yen from 158.43 yen

Euro/pound: UP at 83.41 pence from 83.35 pence

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