LONDON - Oil prices surged to $100 a barrel on Thursday as Tehran-backed Houthi rebels targeted Red Sea shipping and US President Donald Trump threatened to strike them in return.
International benchmark oil contract Brent North Sea soared more than six percent to hit the symbolic $100 level, as the attacks potentially opened a new front in the Middle East war and Trump threatened the Houthis with "major military punishment".
Iran meanwhile vowed to continue striking the Gulf region so long as it remains under attack from US strikes.
Saudi Arabia had been using the Red Sea to export millions of barrels of oil that normally flowed through the Strait of Hormuz, so the closure of that shipping channel would remove more oil from the market.
There are "no signs of a peace deal emerging as the United States and Iran start to dig in and fears rise about choke points for certain fuel supplies", noted Neil Wilson, UK investor strategist at Saxo.
"Investors are in a wary mood... as fresh jitters of worry about the ongoing energy crunch hit sentiment," said Susannah Streeter, chief investment strategist at Wealth Club.
"With both the Strait of Hormuz and the Red Sea now under increasing pressure, markets are bracing for the possibility that the conflict could disrupt key energy routes (and) keep oil prices elevated," she added.
The prospect of higher oil prices also raises the prospect of higher inflation and interest-rate hikes, adding to weak sentiment, analysts said.
European Central Bank head Christine Lagarde said some of its policymakers had considered raising rates at their meeting on Thursday, although all eventually voted to hold rates.
Wall Street's main stock indices all fell more than one percent at the start of trading.
"That isn't surprising given what is going on with Alphabet, Tesla and the mega-cap stocks, oil prices and bond yields," said Briefing.com analyst Patrick O'Hare.
The tech-heavy Nasdaq Composite fell 1.8%.
"The scope of losses at the index level, though, doesn't seem proportional to the gravity of the primary headlines," he added, pointing to other companies receiving a boost after reporting earnings as well as reassuring US unemployment claims data.
All of the so-called Magnificent Seven tech stocks were lower.
Shares in Alphabet fell 6.0%, with some investors taking fright that it raised its AI capital expenditure estimate for the full year to as much as $205 billion, far more than expected.
Shares in Tesla slumped 9.6% after the firm reported weaker-than-expected profits and a doubling of capital expenditures from the same quarter in 2025.
Investors' appetite for all things AI has been tested in recent months on concern about elevated valuations and as they question when the trillions pumped into the sector will see returns.
Next week's results from Microsoft, Meta and Amazon will be pored over for their capital spending plans.
Most Asian stock markets were buoyed by a much-needed bounce for regional tech firms.
European markets were weaker in afternoon trading.
The dollar firmed against its main rivals.
Eyes are on Tokyo after the yen hit a fresh four-decade low against the dollar amid concerns over the gap between the Bank of Japan's low interest rates and those in the United States and other big economies.
Rising oil prices and concerns over Japan's economy have added to pressure on the currency.
Key figures around 1100 GMT
Brent North Sea Crude: UP 5.7% at $99.42 per barrel
West Texas Intermediate: UP 4.5% at $90.75 a barrel
New York - Dow: DOWN 1.2% at 51,613.11 points
New York - S&P 500: DOWN 1.2% at 7,412.95
New York - Nasdaq Composite: DOWN 1.8% at 25,237.60
London - FTSE 100: DOWN 0.9% at 10,699.82
Paris - CAC 40: DOWN 1.8% at 8,288.98
Frankfurt - DAX: DOWN 1.5% at 24,768.13
Tokyo - Nikkei 225: UP 0.5% at 66,422.60 (close)
Hong Kong - Hang Seng Index: UP 1.3% at 25,210.81 (close)
Shanghai - Composite: UP 0.3% at 3,876.78 (close)
Euro/dollar: DOWN at $1.1381 from $1.1411 on Wednesday
Pound/dollar: DOWN at $1.3336 from $1.3372
Euro/pound: UP at 85.33 pence from 85.33 pence
Dollar/yen: UP at 163.77 yen from 163.15
