The few Saturday movements also showed how unusual the remaining traffic had become. They included an empty very large crude carrier whose automatic identification system, or AIS, was switched off, as well as an Indian-flagged very large gas carrier using the Iranian route.

That does not prove that no vessel crossed on Sunday. AIS can be disabled, and some crossings may be recorded later or remain hidden. Bloomberg previously reported that all six commodity carriers it identified crossing on one Sunday had their transponders turned off. The more defensible conclusion is that observable commercial traffic has collapsed, while the true number of crossings is difficult to measure in real time.

Why ships are staying away

The immediate problem is not simply congestion. It is the combination of physical danger, military controls and uncertainty over which routes are safe.

ADNOC said that 15 of its vessels had been attacked by missiles and drones while transiting Hormuz since the beginning of the conflict, including three in one week. The company said the attacks killed one crew member and injured 20 others. Reporting on the latest incidents differs over the exact count and attribution: the UAE blamed Iran for attacks on two ADNOC-linked vessels, while ADNOC separately confirmed attacks on its vessels.

A separate reported attack also increased concern about energy infrastructure beyond the strait. Iran-aligned Houthis said they had struck Saudi Aramco’s Jazan refinery, and the refinery’s restart was postponed to August 30, according to reporting cited by Reuters. Because the refinery strike was attributed to a group aligned with Iran rather than independently established in the supplied reporting, it is best treated as a claimed attack—not definitive proof of responsibility.

The result is a risk calculation that has changed sharply for shipowners and crews. Earlier Kpler data showed vessels turning away from Gulf loading ports after warnings that passage was not permitted, while other vessels stopped near the Gulf of Oman after exiting via the Iranian route.

Oil prices rose, but the market has not priced a total shutdown

Oil reacted immediately to the combination of tanker attacks, refinery damage and uncertainty over reopening. On August 9, Brent crude settled 4.99% higher at $87.72 per barrel, while U.S. West Texas Intermediate rose 5.05% to $82.13.

Prices then showed less momentum. On August 17, Brent was little changed in early trading at $88.72, while WTI slipped to $82.35, even as weekend traffic data showed almost no observable movement and negotiations remained unresolved.

That relative stability does not mean the supply risk has disappeared. It suggests that traders are balancing several possibilities: some oil may still be moving, inventories can cushion a short interruption, and the market may already have absorbed much of the immediate geopolitical premium. A longer disruption—or further attacks on ships and energy facilities—would create a greater risk of another price spike.

Why Hormuz matters beyond shipping

The strait is a critical route for Gulf energy exports. A Dallas Federal Reserve analysis modeled a closure that removed close to 20% of global oil supplies from the market and estimated that such a disruption could lift average WTI prices to $98 per barrel while reducing annualized global real GDP growth by 2.9 percentage points in the modeled quarter. Those are scenario estimates, not a forecast of what will happen in the current episode.

Even without a complete closure, a prolonged slowdown can raise the cost of moving energy. Fewer available ships, longer routes, heightened security requirements and higher insurance premiums can all increase delivered fuel costs. Those costs can then spread through transport, power generation, manufacturing and food supply chains.

The impact is likely to be uneven. Oil-importing economies are more exposed to a sustained rise in fuel prices, particularly where growth is already weak. Reporting on the Philippines cited a BMI forecast that cut projected 2026 growth to 3.9%, a downgrade of about 1.3 percentage points. Separate analysis from MUFG estimated that each $10-per-barrel increase in oil prices could reduce Philippine GDP growth by around 0.2 percentage points and raise inflation by about 0.6 percentage points, although those figures are model estimates rather than observed effects.

The key variable is duration

The weekend’s five-to-zero reading is a warning about the practical accessibility of the waterway, not a precise measure of all oil flows. Kpler has also recorded periods when traffic resumed partially, including days when tankers and LNG carriers passed through after earlier claims that the strait had been closed.

That makes duration more important than any single day’s count. A brief interruption could be managed through inventories, rerouting and limited crossings. A sustained blockade or continuing attacks would put greater pressure on crude and gas availability, shipping costs and inflation expectations.

For now, the evidence supports a cautious verdict: Hormuz traffic has not necessarily reached literal zero, but normal commercial shipping has effectively broken down. Until the security situation improves and a credible reopening arrangement emerges, vessel counts, AIS activity and oil prices will remain the most important indicators of whether the disruption is easing—or becoming a broader economic shock.

The few Saturday movements also showed how unusual the remaining traffic had become. They included an empty very large crude carrier whose automatic identification system, or AIS, was switched off, as well as an Indian-flagged very large gas carrier using the Iranian route.

That does not prove that no vessel crossed on Sunday. AIS can be disabled, and some crossings may be recorded later or remain hidden. Bloomberg previously reported that all six commodity carriers it identified crossing on one Sunday had their transponders turned off. The more defensible conclusion is that observable commercial traffic has collapsed, while the true number of crossings is difficult to measure in real time.

Why ships are staying away

The immediate problem is not simply congestion. It is the combination of physical danger, military controls and uncertainty over which routes are safe.

ADNOC said that 15 of its vessels had been attacked by missiles and drones while transiting Hormuz since the beginning of the conflict, including three in one week. The company said the attacks killed one crew member and injured 20 others. Reporting on the latest incidents differs over the exact count and attribution: the UAE blamed Iran for attacks on two ADNOC-linked vessels, while ADNOC separately confirmed attacks on its vessels.

A separate reported attack also increased concern about energy infrastructure beyond the strait. Iran-aligned Houthis said they had struck Saudi Aramco’s Jazan refinery, and the refinery’s restart was postponed to August 30, according to reporting cited by Reuters. Because the refinery strike was attributed to a group aligned with Iran rather than independently established in the supplied reporting, it is best treated as a claimed attack—not definitive proof of responsibility.

The result is a risk calculation that has changed sharply for shipowners and crews. Earlier Kpler data showed vessels turning away from Gulf loading ports after warnings that passage was not permitted, while other vessels stopped near the Gulf of Oman after exiting via the Iranian route.

Oil prices rose, but the market has not priced a total shutdown

Oil reacted immediately to the combination of tanker attacks, refinery damage and uncertainty over reopening. On August 9, Brent crude settled 4.99% higher at $87.72 per barrel, while U.S. West Texas Intermediate rose 5.05% to $82.13.

Prices then showed less momentum. On August 17, Brent was little changed in early trading at $88.72, while WTI slipped to $82.35, even as weekend traffic data showed almost no observable movement and negotiations remained unresolved.

That relative stability does not mean the supply risk has disappeared. It suggests that traders are balancing several possibilities: some oil may still be moving, inventories can cushion a short interruption, and the market may already have absorbed much of the immediate geopolitical premium. A longer disruption—or further attacks on ships and energy facilities—would create a greater risk of another price spike.

Why Hormuz matters beyond shipping

The strait is a critical route for Gulf energy exports. A Dallas Federal Reserve analysis modeled a closure that removed close to 20% of global oil supplies from the market and estimated that such a disruption could lift average WTI prices to $98 per barrel while reducing annualized global real GDP growth by 2.9 percentage points in the modeled quarter. Those are scenario estimates, not a forecast of what will happen in the current episode.

Even without a complete closure, a prolonged slowdown can raise the cost of moving energy. Fewer available ships, longer routes, heightened security requirements and higher insurance premiums can all increase delivered fuel costs. Those costs can then spread through transport, power generation, manufacturing and food supply chains.

The impact is likely to be uneven. Oil-importing economies are more exposed to a sustained rise in fuel prices, particularly where growth is already weak. Reporting on the Philippines cited a BMI forecast that cut projected 2026 growth to 3.9%, a downgrade of about 1.3 percentage points. Separate analysis from MUFG estimated that each $10-per-barrel increase in oil prices could reduce Philippine GDP growth by around 0.2 percentage points and raise inflation by about 0.6 percentage points, although those figures are model estimates rather than observed effects.

The key variable is duration

The weekend’s five-to-zero reading is a warning about the practical accessibility of the waterway, not a precise measure of all oil flows. Kpler has also recorded periods when traffic resumed partially, including days when tankers and LNG carriers passed through after earlier claims that the strait had been closed.

That makes duration more important than any single day’s count. A brief interruption could be managed through inventories, rerouting and limited crossings. A sustained blockade or continuing attacks would put greater pressure on crude and gas availability, shipping costs and inflation expectations.

For now, the evidence supports a cautious verdict: Hormuz traffic has not necessarily reached literal zero, but normal commercial shipping has effectively broken down. Until the security situation improves and a credible reopening arrangement emerges, vessel counts, AIS activity and oil prices will remain the most important indicators of whether the disruption is easing—or becoming a broader economic shock.