The sixty-day memorandum of understanding signed by the United States and Iran on 17 June expired on 18 August without renewal. Its most consequential clause concerned the Strait of Hormuz, the twenty-mile channel through which a quarter of the world’s seaborne oil normally passes. For two months, some of it did again. Then the window shut.
How much moved is now a matter of measurement rather than announcement. The trade intelligence firm Kpler, which tracks tanker movements by satellite, estimates that 374 million barrels left the Gulf during the window — about 6.1 million barrels a day. That is nearly triple the 2.3 million barrels a day the firm recorded between April and mid-June, and roughly forty per cent of what the strait carried before the war. More than half of it moved in the first three weeks. Kpler’s Emmanuel Belostrino described the flow as ending “thinner, darker and re-accumulating behind the chokepoint.”
The baseline is worth holding in mind. The International Energy Agency’s February factsheet puts 2025 transit at an average of 20 million barrels a day, about a quarter of global seaborne oil trade, alongside 112 billion cubic metres of liquefied natural gas — close to a fifth of the world’s LNG. The US Energy Information Administration’s March update gives a similar figure, 20.9 million barrels a day in the first half of 2025. Against those numbers, two months of partial passage restored a fraction, not a flow.
Crude has responded in the direction one would expect. Brent settled near $94 a barrel on Thursday, up about two and a half per cent on the day; West Texas Intermediate closed around $88.40. President Donald Trump has said Washington will pursue “economic warfare and isolation on an unprecedented scale.” Iran’s central bank governor, Abdolnaser Hemmati, told state television plainly: “It is a reality that we are not exporting oil.”
A strait is not a switch. It reopens by degrees, and it has not yet.