Oil flows through Hormuz fall 27% as tanker attacks escalate during war
Key Facts
Crude oil volumes passing through the Strait of Hormuz fell 27% from a wartime peak recorded the previous week, according to a Kpler note dated 6 October 2026 cited by Reuters. The decline came as attacks on tankers escalated along the route used by Gulf oil exporters, renewing concerns over Middle Eastern supplies. Reuters reported that tanker attacks reached their highest weekly level since the war with Iran began in the previous week. That wave of attacks coincided with increased exports by Gulf producers, before crude flows through the strait fell from their wartime peak. Investing cited the United Kingdom Maritime Trade Operations as recording 9 attacks in the strait from the start of October through its report on 7 October.
On shipping traffic, 7 vessels carrying commodities crossed the strait on the Tuesday preceding the Reuters report published on 8 October, according to shipment-tracking firm Kpler. That was the lowest number of crossings since late July, following attacks on shipping in the region. Before the war with Iran, about 125 large commercial vessels passed through the strait daily, according to background on trade through the waterway provided by Reuters. Those large commercial vessels included oil and gas tankers, as well as bulk carriers and container ships. Other vessels cross the waterway with their automatic identification systems switched off to avoid detection, outside the traffic tracked by Kpler and reported by Reuters.
In its estimate of oil shipment volumes, Kpler put crude flows through the Strait of Hormuz at no less than 10.1 million barrels per day, according to an update cited by Reuters on 8 October. Those flows stood at 74% of their pre-war level, according to the company, as oil continued to pass through despite escalating maritime attacks. Meanwhile, crude exports from the Gulf of Oman coast and the Red Sea rose to 6.7 million barrels per day, according to Kpler analysts cited by the agency. Increased exports from those two areas offset oil supplies lost through Hormuz, as crude flows through the strait fell from their wartime peak. The replacement supplies shipped through Gulf of Oman and Red Sea outlets were part of Gulf producers' export activity during the wave of maritime escalation.
In oil markets, Brent crude futures traded at $101.53 per barrel in early trading on 8 October 2026, according to Reuters. The agency attributed the rise in oil prices to persistent concerns over Middle Eastern supplies amid increased attacks on shipping. The market had previously seen a wave of escalation in September, when Iran and the United States exchanged strikes on tankers, according to an earlier report by the agency. Brent closed on 9 September at $101.21 per barrel, after a daily gain of 3.4% in that session. Crude's rise during the September escalation was linked to the intensifying conflict in the Middle East, while early October trading came amid renewed supply concerns as maritime attacks continued.
Alongside the maritime developments, the U.S. Treasury Department announced measures targeting 17 vessels in Iran's shadow fleet on 8 October 2026. The department said in its statement that the targeted vessels transport crude oil, petroleum products and petrochemicals to markets in South and East Asia. The U.S. action thus covered vessels transporting Iranian crude, petroleum products and petrochemicals to Asian destinations. Treasury Secretary Scott Bessent warned those helping Iran evade sanctions that the department would use its full authority against them. Bessent said in the statement: "No party facilitating Iranian sanctions evasion will be immune from the full use of Treasury's authorities," in a warning accompanying the announcement of measures against the vessels.
On measures to support supplies, governments of International Energy Agency member countries backed prioritising releases of diesel stocks, according to the agency's statement on its meeting on 7 October 2026. The agency linked that approach to tight diesel markets, stressing that priority should be given to releasing diesel stocks wherever possible. Member governments' support focused on stocks of that fuel as part of their response to the supply conditions discussed at the meeting. The agency said its members would continue to assess the situation at its governing board meeting scheduled for the week following its statement. The board meeting in the week after the 7 October statement will be the agency's next opportunity to assess the situation, after member governments endorsed prioritising diesel in stock releases.