Hormuz "Dark Currents" Accelerate: 65% of Tankers Transit in "Dark Mode"
Miles Bennett
About 65% of laden tankers leaving the Persian Gulf in May crossed the Strait of Hormuz with their AIS transponders switched off, making the official 'three ships a day' figure a gross undercount. This means → the supply-demand data underpinning global oil pricing is being systematically distorted, forcing markets toward alternative gauges of real flow.
Official data says "three ships a day" — what's the real volume?
Since the conflict began, LSEG and Kpler have tracked only about 3 tankers a day entering or leaving the strait — roughly one-tenth of pre-war normal.
Yet in May, about 65% of laden tankers switched off their AIS — the automatic identification system that broadcasts a vessel's position — and transited in "dark mode."
This means → visible traffic is just the tip of the iceberg. Actual export volumes are far higher than tracking data suggests.
If the ships are invisible, how do we know oil is flowing out?
The key alternative indicator is "floating storage" inside the Persian Gulf — total crude held on tankers trapped inside the strait.
Kpler data shows floating storage has fallen from a March 22 peak of 184 million barrels to about 148 million barrels this week — a drawdown of roughly 36 million barrels.
The May drawdown rate accelerated to about 710,000 barrels per day, up from the conflict-average of roughly 500,000 b/d. In plain terms = the oil is leaving faster; we just can't see the ships.
What routes are these "dark" tankers taking?
According to Reuters, some vessels may be using bilateral arrangements between Iran and countries including Pakistan, India, China, and Japan, transiting within Iranian-designated corridors.
Some tankers may even be paying Iran a "safe-passage fee"; others may be routing close to the Omani coast.
A further possibility: transit with the tacit consent or active assistance of the U.S. Navy. This reflects a reality where all parties are quietly keeping oil moving — the geopolitical game is playing out beneath the surface.
Can oil-price benchmarks still be trusted?
Visibility on cargo flows and destinations has dropped sharply, making the supply-demand flow data that underpins benchmark prices increasingly hard to verify.
This means → conventional tracking methods are failing. Alternative indicators such as floating-storage volumes are rising sharply in importance.
In plain terms = markets used to count ships to gauge supply; now the ships have "vanished," so analysts must work backwards from how fast the warehouse empties.
What's the real bottleneck for a supply recovery?
Even if tensions ease, one logistics chokepoint remains: empty tankers must be able to return steadily to the Gulf to load, creating a sustainable "laden-out, ballast-in" cycle.
That cycle has not yet been established at scale. Shipowners and charterers remain cautious about entering high-risk waters; insurance premiums still price in elevated risk.
Whether roughly 11 million b/d of shut-in capacity can restart depends on the predictability of export routes. The fragile flow sustained by "dark mode" is not yet enough to underwrite that confidence.
Content is for reference only, not financial advice.