Hormuz Shut Since May 5 — No Tankers Through, Diesel Still Climbing
Iran halted all transits through the Strait of Hormuz three days ago and imposed new shipowner reporting rules. Crude and diesel prices remain elevated despite Tuesday's brief dip.
No oil tankers have passed through the Strait of Hormuz since May 5, when Iran tightened control of the waterway and began requiring shipowners to submit detailed vessel information to its Persian Gulf Strait Authority.
How long has the Strait of Hormuz been closed?
The closure entered its fourth day May 8. Tehran's new reporting requirement effectively halted all commercial transits through the 21-mile-wide channel that carries roughly 20% of global oil supply. The US and Iran remain in a military standoff in the region, with no timeline announced for reopening the strait.
What the closure costs a small fleet
Diesel averaged $4.48 per gallon nationally as of May 5 — up $1.32 year-over-year and 31 cents in the prior week alone. A five-truck fleet running 500 miles per day per truck at 6.5 mpg burns roughly 385 gallons daily. At current prices, that's $1,725 in fuel cost per day, or $345 per truck. The same operation paid $1,217 daily a year ago — a $508 daily increase, or $3,556 per week.
Brent crude briefly fell 5.7% to $103.61 per barrel May 6 on speculation that Iran and the US might reach a deal to reopen the strait, but no agreement materialized and prices have since climbed back above $108. The May 6 dip translated to a $0.27-per-gallon diesel drop that would have saved the hypothetical five-truck fleet $104 daily — savings that evaporated within 24 hours as the closure persisted.
Why Iran's new reporting rule matters
The Persian Gulf Strait Authority now requires shipowners to file detailed vessel data before entering Hormuz waters. The rule gives Tehran effective veto power over which tankers pass and when, even if the waterway physically reopens. Shipowners face the choice of submitting to Iranian oversight or rerouting around the Cape of Good Hope — a detour that adds 3,500 miles and two weeks to a Middle East-to-Europe voyage.
Longer tanker routes tighten global oil supply even if Iran eventually lifts the transit ban. Refiners pass those delays and higher shipping costs through to wholesale diesel, which filters down to the pump price a small fleet pays.
The fuel spike's timing problem for carriers
Contract rates climbed 8% from fall 2025 through mid-2026 as capacity stayed tight and tender rejection rates remained elevated, but fuel surcharges in many contracts lag spot diesel moves by two to four weeks. A carrier locked into a January contract rate with a lagging FSC is now absorbing the $1.32-per-gallon year-over-year diesel increase out of margin until the surcharge catches up — if it catches up at all before the contract renews.
Spot freight rates have improved in recent weeks, giving carriers more leverage to pass fuel costs through on the spot market. But fleets running a mix of contract and spot freight are still eating part of the diesel spike on their contract book.
What happens if the strait stays shut
Every week Hormuz remains closed pulls another 35 million barrels of crude off the market — roughly 5 million barrels per day that would normally flow to refineries in Europe and Asia. US diesel inventories can buffer domestic prices for a few weeks, but sustained closure pushes crude above $110 and diesel toward $5 per gallon or higher. At $5 diesel, the five-truck fleet's daily fuel bill hits $1,925 — $200 more than today and $708 above last year.
The US and Iran have not announced talks to resolve the standoff. Until transits resume, diesel prices will track crude, and crude will track how long shipowners are willing to wait outside Hormuz or reroute south.
