Hormuz Traffic Fell From 130 Ships a Day to 8, and Oil Rose 16%

Between August 4 and 6, eight to fifteen ships a day crossed the Strait of Hormuz, against 130 before the war. A quarter of the world's seaborne oil and a fifth of its LNG moves through it — or used to.

That week the S&P 500 set a record, touching 7,700. The market priced a reopening; what Iran put on the table is a transit regime: lanes, fees, penalties.

A Door Shut in February, a Rulebook Written in August

It began on February 28, when the Revolutionary Guard forbade passage after a joint US-Israeli air campaign. Tankers were struck in early March, traffic fell roughly 70%, more than 150 ships anchored outside, and the closure was declared on March 2.

Brent crossed $100 on March 8, the first time in four years, and ran to $126; Dubai hit a record $166 on March 19. IEA members released 400 million barrels on March 11, and Saudi Arabia cut output 20% on March 13, to 8 million barrels a day from 10 million.

August is different. On August 7 Iranian state media said Tehran and Muscat had agreed an arrangement. Inbound ships take a northern Iranian lane, outbound ships a southern Omani lane.

American and Israeli-flagged vessels are barred, and violators face fines of up to 20% of cargo value. States judged to have harmed Iran cannot pass until they pay.

Traffic management and pollution control fall to Iran, and there is a fee. During the April ceasefire Iran charged tolls above $1 million per ship, now tied to "a combination of variables". Araghchi called a deal "very close" on August 8, then on August 10 demanded sanctions relief and reparations; Brent rose 1% to $84.43.

The Ceiling on the Bypass

Saudi Arabia's 1,200-kilometer Petroline, built in 1981 for 5 million barrels a day, reaches an emergency 7 million after post-2019 upgrades, as on March 11. The UAE's 380-kilometer line to Fujairah is rated 1.5 million and ran at 71% in mid-March. Together, at best, that is 8.5 million a day, two-fifths of the 20 million that normally transits.

A pipeline is only as useful as its port: Yanbu loads a nominal 4.5 million barrels a day, realistically 3 million in wartime. For gas there is no bypass.

The Difference Between a Cost and a Prohibition

The war-risk premium is the surcharge for entering a war zone. It was 0.125% of hull value in calm 2025 conditions, 0.25% in early February 2026, and 3% to 10% by July, per Marsh's Marcus Baker.

For a $100 million tanker, $250,000 a voyage became $3 million to $10 million. Serious, and payable.

A cost that can be passed on stays inside the price system: freight rises, crude gets dearer, the ship sails. A penalty that wipes out the voyage takes that system offline. The question becomes "am I allowed", and underwriters exit exactly there: one who withdraws cover has forbidden the voyage.

That is why 130 ships a day became eight: what closed the strait was not ordnance but the size of the fine.

Why Crude Is Only 16% Higher

Three-fifths of the flow is severed, yet Brent sits just 16% above pre-war, down from $126 in March. Three buffers are at work.

Demand: China cut inbound shipments roughly 40% in May year on year, refinery runs falling from 14.8 million to about 13 million barrels a day, a 1.8 million reduction. Supply: US crude and fuel exports ran more than 2 million barrels a day above the 2025 average. Inventories: the stock draw is 70 million to 80 million barrels a week.

Two are flows, one is a stock: demand and exports repeat every week, a stock draw only depletes. The IMF said as much in mid-July — the shock was absorbed, the buffers are low. An $84 barrel says the tank is draining at about 10.7 million barrels a day, roughly the volume that cannot leave the Gulf.

Across the 160 days the strait has been shut, the US equity market has kept climbing.

The energy-equity story differs: as crude rose, Exxon Mobil followed its own path — a barrel stuck in the Gulf is a different equation for a producer outside it.

The Other Side

What to Watch This Week

The strait's story meets the consumer price index on August 12. Brent rose about 24% in July and WTI about 21%, and that print is the first inflation reading after the move.

The Financial Times, citing unnamed sources, reports Fed Chair Kevin Warsh is open to a September rate rise if the data run hot. The 30-year Treasury yield is near 20-year highs. Oil passes into inflation quickly — pump prices reach the headline index within weeks, making the strait an input to the rate path.

This piece draws on Al Jazeera's market and diplomatic reporting of August 5, 8 and 10, NPR's account of the Iran-Oman arrangement, International Energy Agency data on the Strait of Hormuz, Engineering News-Record's analysis of bypass infrastructure, The National's Marsh-sourced reporting on war-risk premiums, and the International Monetary Fund's July assessment. The text of the arrangement was announced through Iranian state media and has not been publicly confirmed by Oman; the reporting on Warsh rests on unnamed sources. Prices are as of the London morning session on August 10.

Correction (September 13, 2026): prose tightened for rhythm; figures and sources unchanged.