Brent has added 42 percent on a strait that stopped changing a month ago

Tehran's wire says crude is climbing because Hormuz traffic is falling. On this site's count the traffic stopped falling on 14 August, and the price has risen 42 percent since.

Published 2026-09-19 · analysis

The strait and the oil price have come apart, and they have been apart for a month. Since 14 August the seven-day average of vessels crossing Hormuz has sat in a band between 3.1 and 6.0 a day, averaging 4.3 over the whole thirty-one days and finishing at 5.3 on 13 September, the last day this record counts. Brent across the same thirty-one days went from $92.02 to $130.80. One of those two series is carrying information, and it is not the one about ships.

It is worth being precise about how little moved. August ran at 4.71 vessels a day and the first thirteen days of September at 4.31; the tonnage those ships could carry was 0.090 Mt a day in August against 0.105 Mt in September. Both gaps are smaller than the week-to-week scatter inside either month, which is another way of saying nothing happened. Nothing in the physical record marks the start of September, and September is where the price went.

Where it went was $130.80 on 15 September, up 45.7 percent from $89.75 in eleven sessions and the highest official close since 7 April, the peak of the whole crisis. Of the 9,087 Brent closes since 1987, only thirty are higher: twenty-eight in the summer of 2008, one in March 2022, and 7 April this year. That is a serious number arriving on top of a flat one.

Both parties to the argument are describing the flow anyway. Trump wrote on 14 September that oil is flowing through the strait; the next morning Mehr ran “Hormuz shipping traffic declines, crude prices climb”, which is Tehran claiming the rally as its own work. Mehr has run nine such bulletins since 17 August, and every one of them is Mehr’s — neither IRNA nor Tasnim has filed one — the latest reporting three vessels on Wednesday. They started three weeks after IRNA called Hormuz transit figures “mere propaganda, not facts”. Across the thirty-one days those bulletins cover, the count did not fall.

It did not fall because there is nothing left to take out. At 4.3 vessels a day against 58.5 in January, the strait is running at seven percent of normal, and two ships a day either way is noise on a base that has already collapsed. So the transit count has stopped being able to explain the oil price in either direction: it cannot fall much further, and it did not need to for Brent to add forty-two percent. Whatever prices the next leg will not show up as ships failing to get through, because they already are not. This site found on 4 September that the one Hormuz channel Brent still trades is an American airstrike; a month of flat transits under a forty-two percent rally is what that looks like from the water.

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