Brent crude closed at $100.32 on October 5 while WTI closed at $89.22, a gap of $11.10 that has more than doubled from $4.89 on September 8. Canadian producers measure their results against WTI, not Brent, so the Strait of Hormuz premium is reaching them only in part. Suncor, for one, ties its targets to WTI: its CEO said on October 4 that the company's commitments to "reduce WTI breakeven remain unchanged."
The widening is not mainly a Hormuz story. Analysts at StoneX and Standard Chartered tie it to a U.S. policy threat on diesel exports, which weighs on the domestic crude price while seaborne barrels stay expensive.
Why Brent Holds $100 While WTI Does Not
Brent closed at or above $100 on 12 of the 20 sessions between September 8 and October 5 and is 7.75% below its September 15 peak of $108.75. WTI is 12.94% below its September 10 peak of $102.48. The two benchmarks started the period 4.89 dollars apart and now sit more than 11 dollars apart.
The turn came on September 22, when President Trump said of diesel: "Let's not send out the diesel. We make a lot of diesel." Benzinga reported that he later told Fox News the administration was "thinking about it very seriously." Diesel prices hit a record $6.53 a gallon in late September, up 42.6% since July 10, per the same report.
The Brent-WTI gap was $4.89 on September 8 and $11.10 on October 5. Brent closed at or above $100 on 12 of the 20 sessions. Spreads quoted by other outlets differ with contract month and time of day.
The mechanism runs through refiners. David Scutt of StoneX said the spread "implies weaker refinery demand for WTI relative to Brent," and Emily Ashford of Standard Chartered said the market is pricing "the risk of a not-immaterial cut to U.S. refinery runs." An export ban would trap diesel in the United States, refiners would run less, and they would buy less crude.
Hormuz Is Reopening, and Is Under Fire
Crude flows through the strait averaged 16.5 million barrels a day from September 1 to 28, or 87% of the pre-war 19 million, according to the Seoul Economic Daily. Saudi exports rebounded to 6.9 million barrels a day in September from 2.45 million in August.
Seven vessel attacks have been reported near the strait since September 28. Hamad Hussain, senior economist at Capital Economics, said the attacks "show how fragile the current balance in the oil market is." Rory Johnston of Commodity Context said "the recent pace of shipments is impressive but by no means sustainable, and has come at an enormous cost."
The Red Sea bypass carries its own risk. Al Jazeera reported that the Houthis declared a blockade on Saudi-linked vessels in July, and on August 24 Bahri confirmed an incident involving its tanker Amzan off Yanbu, Saudi Arabia's main Red Sea export hub, with all crew safe.
As of the August 17 report, 300 million of the 400 million barrels pledged had been released and more than 100 million had yet to reach the market. The U.S. Strategic Petroleum Reserve released 17 million barrels in July, about half the June volume.
The stock release has also been winding down. The IEA coordinated action averaged 2.5 million barrels a day in May and 750,000 in July, and the agency said the timing of the remaining releases depends on market developments. A thinner cushion leaves more weight on tanker traffic through Hormuz and the Red Sea.
What Canadian Boards Did With the Gap
On October 5, Cenovus agreed to buy Athabasca Oil for $12.00 a share in cash, 0.264 Cenovus shares or a combination, an implied enterprise value of $5.7 billion in Canadian dollars. The deal is expected to close in December. CEO Jon McKenzie called it "a natural extension of our oil sands strategy."
A day earlier Suncor agreed to sell its stakes in Terra Nova (48%), White Rose (40%) and West White Rose (38.6%) for $1.2 billion upfront, with up to $350 million more contingent on future oil prices. About 23% of the maximum value of $1.55 billion therefore depends on where oil trades, and the sale is expected to close in early 2027.
The two deals show the range of structures in use. One buyer is paying a fixed price in cash or shares for oil sands assets, and one seller is accepting a payment tied to future oil prices for offshore assets.
Base Case and Tail Risks
The base case is a market near $100 Brent with a persistent WTI discount. Capital Economics expects Brent to "hold around $100 a barrel through the end of the year." The gap narrows if diesel export talk fades, and widens if it becomes an order.
Two tail risks stand out. A formal diesel export ban would cut U.S. refinery runs and push WTI lower while Brent stays supported, which would widen the discount facing WTI-linked Canadian producers. A successful strike on Yanbu would hit a bypass route for Saudi exports. Neither is the expected outcome, and both are non-trivial.
The signals to watch are whether the diesel comments become a formal order and whether the pace of tanker attacks near Hormuz continues.