LONDON: Oil prices plunged more than 10 per cent on Friday after Iran said the Strait of Hormuz would be “completely open” for the rest of the ceasefire with the United States, and stock markets surged.

Brent North Sea crude tumbled 10.7pc at $88.74 a barrel and the West Texas Intermediate plunged 11.1pc at $81.07 a barrel.

Iran’s Foreign Minister Abbas Araghchi said on X that “passage for all commercial vessels through Strait of Hormuz is declared completely open for the remaining period of ceasefire”.

The strategic waterway, through which one-fifth of the world’s crude oil normally flows, has been disrupted by Iran since the US-Israeli offensive began, at one point sending oil prices to a peak of nearly $120 a barrel and threatening to disrupt the global economy.

Both Brent, the benchmark international contract, and its US equivalent WTI fell below $90 per barrel following Tehran’s announcement.

“This news is having an immediate impact on markets,” said Kathleen Bro­oks, research director at XTB.

Wall Street’s main stock indices jumped higher, with both the S&P 500 and the Nasdaq Composite building on record highs struck Thursday.

“This is the biggest development so far during the ceasefire, and it gives hope that the war will end soon, and supply chains will return to some normality,” Brooks said.

It was not clear whether Araghchi was referring to the 10-day truce agreed to by Lebanon and Israel, which went into effect late Thursday, or to an earlier two-week truce between Iran and the United States that began on April 8.

But Araghchi’s declaration bolstered hopes for further peace talks and a renewal of the ceasefire, despite US President Donald Trump saying that the US blockade of Iran’s ports remains in force.

Meanwhile, France and Britain announced they will lead a multinational mission to ensure freedom of navigation in the Strait of Hormuz.

They stressed the force would be entirely defensive — and only deployed once a peace in the region was agreed.

David Morrison at Trade Nation noted that the speed and magnitude of the S&P 500’s rebound — nearly 12pc in just over two weeks — were reinforcing the rally. European stocks closed higher, with both Fran­kfurt and Paris gaining 2pc.

Asian stock markets mostly closed lower, before Iran’s announcement, with Tokyo among the biggest losers after reaching a record high Thursday, and Taiwan’s TAIEX index dropped after hitting a market capitalisation of $4.14 trillion.

That put the index ahead of London’s benchmark FTSE 100 and made the TAIEX the world’s seventh-biggest index by value, according to Bloomberg data.

Published in Dawn, April 18th, 2026