Traders work on the floor of the New York Stock Exchange during morning trading on April 17, 2026 in New York City.
Michael M. Santiago | Getty Images
Stock futures tumbled Sunday night as tensions between the U.S. and Iran escalated over the weekend with the seizure of an Iranian-flagged cargo ship.
Dow Jones Industrial Average futures shed 425 points, or 0.9%. S&P 500 futures lost 8%, along with Nasdaq-100 futures.
President Donald Trump on Sunday said the U.S. had fired on and seized an Iranian-flagged cargo ship in the Gulf of Oman. This comes after Iran declined to join another round of peace talks in Pakistan planned by the U.S.
The Iranian ship “is under U.S. Treasury Sanctions because of their prior history of illegal activity. We have full custody of the ship, and are seeing what’s on board,” Trump said in Truth Social post.
Trump also threatened to blow up all power plants and bridges in Iran if the country didn’t agree to a deal with the U.S. A ceasefire between the two countries will expire this week.
Crude prices surged in early trading. West Texas Intermediate futures popped 7% to $90.33 per barrel. International Brent advanced 7% as well to $96.88.
Wall Street is coming off a winning week, with the S&P 500 and Nasdaq Composite climbing to all-time highs following a ceasefire between Iran and Lebanon. At the time, Iran had declared that the Strait of Hormuz was reopened, though by Saturday vessel traffic through that key shipping lane was restricted again, with state media saying the U.S. “did not fulfill their obligations.”
Trump has reiterated that the U.S. blockade of the strait would remain in place until Iran agreed to U.S. demands, despite the Iranian declarations.
The S&P 500 last week gained 4.5%, while the Nasdaq Composite popped 7.2%. The latter also posted on Friday its 13th consecutive winning session, matching a streak not seen since 1992.
Stocks were also lifted by a string of solid quarterly results. More companies are slated to report this week, including Tesla, Boeing and Intel.
Oil surges after Iran-flagged ship seized
U.S. struck and seized Iranian-flagged cargo ship in Gulf of Oman, says Trump
The U.S. struck and seized an Iranian-flagged cargo ship in the Gulf of Oman, President Donald Trump said Sunday.
In a post to Truth Social, the president said the U.S. intercepted a ship called the TOUSKA in the Gulf of Oman and gave it a warning to stop. The vessel was fired upon when it did not stop. The U.S. has been operating a naval blockade of ships entering and exiting Iranian ports since last week.
“The Iranian crew refused to listen, so our Navy ship stopped them right in their tracks by blowing a hole in the engineroom,” Trump said in the post. “Right now, U.S. Marines have custody of the vessel. The TOUSKA is under U.S. Treasury Sanctions because of their prior history of illegal activity.”
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— Garrett Downs
