Dow Jones, S&P 500, NASDAQ decline as US launches 10th straight night of strikes on Iran

The US markets ended the session with losses on Monday, July 20, as the military exchange between the United States and Iran continued.

The Dow Jones Industrial Average dropped 0.59% to settle at 51,839.26, while the S&P 500 declined 0.19% to 7,443.28. The NASDAQ Composite fell 0.05% to end at 25,508.07.

Taking to Truth Social, US President Donald Trump said that every time Iran kills an American soldier, they will have to pay for that "killing many times over."

"This directive has been passed on to Secretary of War, Pete Hegseth, Chairman of the Joint Chiefs of Staff, Daniel Caine, and every Leader in the Military," he said.

US Central Command, in an X post, said that it has completed 10th straight night of strikes against Iran, targeting military command centers, maritime capabilities, missile and drone launch sites and air defence systems to degrade Tehran's ability to continue attacking commercial vessels passing through the Strait of Hormuz.

It claimed that the transits of commercial vessels through the key international maritime corridor continue. "Since early May, CENTCOM forces have helped facilitate the transit of approximately 900 commercial vessels and 450 million barrels of crude oil," it said.

"American forces remain postured and prepared to hold Iran accountable for unwarranted aggression toward civilian mariners seeking to freely and openly transit the strait," it added.

Additionally, US President Donald Trump imposing 50% tariffs on most Canadian goods also impacted investors' sentiments.

Brent crude, the international standard, slipped 0.57% to $88.69 a barrel, which is still higher than pre-war levels. West Texas Intermediate dropped 0.15% to $82.36 per barrel.