Iran has issued a blanket warning covering the entire fleet of South Korean tanker giant Sinokor, saying the company will face sweeping action from 1 November if it keeps violating Tehran's protocol for shipping through the Strait of Hormuz. The notice, from Iran's Persian Gulf Strait Authority, is the first blanket warning covering a shipowner's whole fleet, according to the reporting, and it lands on a company that alone accounted for about 37% of Hormuz oil transits in September.

The scale of Sinokor's role explains why the warning matters beyond one company. Lloyd's List Intelligence data cited in the reporting puts Sinokor at more than 50% of very-large-crude-carrier traffic through the strait in the first 10 days of October, and at least seven Sinokor-linked tankers have been attacked and struck by Iranian missiles or drones recently and during the conflict. Very-large crude carriers are the biggest oil tankers, and rates for them have soared more than 1,600% this year amid the disruptions caused by the war.

Insurance costs tell the same story

Before the war that began on 28 February 2026, Hormuz war-risk cover typically cost 0.15% to 0.25% of hull value, according to Lloyd's List. By early October 2026, brokers were quoting 6% to 10%, according to the Financial Times, a jump that shows how far risk pricing has moved even before any fleet-wide action takes effect. New very-large crude carriers cost 125 million to 135 million dollars to build, while a prompt-delivery resale can run much higher, especially now.

What the unspecified action against Sinokor would actually involve remains to be seen, and the warning itself is a threat, not yet a confirmed enforcement step. For oil markets, though, a fleet-wide warning against the strait's dominant carrier, with freight and insurance costs already extreme, is another reason the Hormuz disruption continues to set the price of moving oil.