Iran declared the Strait of Hormuz completely open for commercial vessels this morning, April 17, sending oil prices into a sharp decline and stocks to new all-time highs.
Brent crude fell more than 11% to around $88 per barrel. WTI dropped about 12% to nearly $83. Jet fuel futures plunged 13%. Gasoline futures fell 7%. The seven-week margin window that made Gulf Coast refiners the most profitable operators in the world just shifted, fast.
The question every Gulf Coast refinery operator, plant manager and procurement team needs to answer today is not whether this changes things. It does. The question is how fast, how much and what you do about it in the next 72 hours.
Here is the full picture: what happened this morning, what the IEA's April 2026 Oil Market Report said three days ago before anyone knew the Strait would reopen today, why Gulf Coast operators were winning and what happens to that advantage from here.
What happened this morning
Iranian Foreign Minister Abbas Araghchi posted this morning that commercial vessel passage through the Strait of Hormuz is declared completely open for the remaining period of the ceasefire, on a coordinated route. The announcement was tied to the separate Israel-Lebanon ceasefire that went into effect yesterday evening.
President Trump celebrated the news on Truth Social and said the U.S. naval blockade of Iranian ports and coastal areas remains in full force until a permanent deal is reached. He added that negotiations should go very quickly. The EU's top diplomat Kaja Kallas said under international law, transit through the Strait must remain open and free of charge, calling any pay-for-passage toll scheme a dangerous precedent for global maritime routes. France's Macron said the Strait needs to be secured by a neutral, independent party. A planning meeting on that framework is scheduled in London next week.
Three things are still unresolved. Mines are in the water. War-risk insurance premiums remain elevated. And the two-week ceasefire expires April 21, four days from now. JPMorgan analysts noted this week that the last tanker to clear Hormuz on February 28 is expected to reach its destination around April 20, the point at which pre-closure barrels are fully exhausted from the global supply chain. The timing is not coincidental.
Whether shipping companies that suspended Hormuz transits weeks ago will immediately reverse course is not clear. Physical flow resumption will lag the political announcement.
What the IEA's April 2026 oil market report said
The IEA released its April 2026 Oil Market Report on April 14, three days before this morning's announcement. It is the most authoritative dataset available on what Gulf Coast operators were actually running through. Every number in this section reflects the environment that produced the margin spike. Understanding it tells you how far the market has to travel to normalize.
Flows through the Strait of Hormuz dropped from roughly 20 million bpd before the war to approximately 3.8 million bpd in early April. Global oil supply fell 10.1 million bpd in March alone. Cumulative supply losses exceeded 360 million barrels in March. The IEA projects 440 million barrels lost in April. Middle East and feedstock-constrained Asian refineries cut runs by 6 million bpd in April, dropping global crude throughputs to 77.2 million bpd. The IEA now projects global crude runs declining 1 million bpd for the full year 2026.
Refining margins surged in response. Middle distillate cracks hit all-time highs. U.S. ultra-low sulfur diesel futures were trading at more than $72 per barrel above WTI. Before the conflict that premium was roughly $40. Gasoline futures were near $26 above crude, up from $18. Gulf Coast refinery utilization climbed above 95%, against a five-year seasonal average of roughly 82%.
The IEA's base case, written three days ago, assumed oil shipments would gradually resume from May, allowing recovery through the third quarter of 2026. This morning's announcement accelerates that timeline on paper. What it means in practice depends on whether ships move and whether the ceasefire holds past April 21.
Why Gulf Coast refiners were winning
For the past seven weeks, Gulf Coast refiners operated from a structural position their global competitors could not match. They run on domestic light shale crude from the Permian Basin, priced at WTI. That feedstock does not transit the Strait of Hormuz. As Asian and Middle Eastern refineries cut runs for lack of feedstock, Gulf Coast operators ran hard and sold diesel, jet fuel and gasoline into markets where supply was genuinely scarce.
The WTI-Brent spread widened from roughly $6 per barrel before the conflict to $12 by March. Gulf Coast operators were buying cheaper crude and selling products priced against surging global benchmarks. Physical crude prices near $150 per barrel for Brent-linked grades, compared to WTI at a significant discount, created an arbitrage that benefited every barrel of domestic-feedstock-based production on the Gulf Coast.
Valero, Marathon Petroleum, Phillips 66 and PBF Energy were the primary beneficiaries, given their feedstock access, Colonial Pipeline connections and deep-water export terminals positioned to supply Europe, Africa and Asia with product those markets could not get anywhere else.
Valero added Venezuelan heavy crude into the mix, sourcing up to 6.5 million barrels through Chevron in March alone, making it the top foreign refiner of Venezuelan oil during that period. Venezuela's Merey blend was offered at roughly $10 below Brent in late March. For facilities with coking capacity, that feedstock discount compounded crack spreads that were already at record levels.
"U.S. refiners have the upside opportunity of selling into markets facing scarcity, while not having to suffer any meaningful disruption to their own feedstock supply," said Jeff Krimmel, founder of Krimmel Strategy.
"Strength in global diesel markets is expected to pull barrels from the U.S. Gulf Coast, ultimately contributing to further upward pressure on domestic prices," said Alex Hodes, director of energy market strategy at StoneX.
For Gulf Coast petrochemical producers running on ethane from Permian and Haynesville natural gas, the advantage was similar. Ethane-based crackers do not need Middle Eastern naphtha. While Asian crackers cut runs as naphtha and LPG supplies dried up, Gulf Coast ethane crackers kept operating and sold into a tighter global market for ethylene derivatives.
What changes now and how fast
A 10 to 12% crude price drop compresses crack spreads immediately. Product prices will follow crude lower as Middle Eastern supply expectations shift, though product markets normalize more slowly than crude markets. Refinery restarts take time. Physical damage to Middle Eastern energy infrastructure is real. Nearly 3 million bpd of regional refining capacity shut due to attacks and lack of export outlets. Restart timelines for damaged facilities are measured in months, not days.
Energy Aspects founder Dr. Amrita Sen has consistently noted that once the Strait reopens, competition from Asian markets will move fast to reclaim market share. That process begins today. But the pace matters. IEA data shows global observed oil inventories fell 85 million barrels in March, with stocks outside the Middle East Gulf drawn down by 205 million barrels. Restocking that supply chain takes time. The physical market will remain tighter than futures prices suggest for weeks, possibly months.
GasBuddy analyst Patrick De Haan said this morning that the shift in crude prices could send the national gasoline average below $4 per gallon this weekend, to perhaps $3.65 to $3.85, down from $4.09 this morning.
For Gulf Coast operators, the next few weeks are a transition period. The peak of the margin window has likely passed. But the market does not normalize overnight. Operators who have been running hard and selling into export markets retain an advantage while Middle Eastern competitors work through the restart process.
Four things to watch right now
The ceasefire expires April 21. A four-day window is not a peace deal. If talks break down before a permanent agreement is reached, this morning's announcement could reverse quickly. Trump said Thursday the two sides would probably meet this weekend, but no date has been confirmed. Several European and Gulf Arab leaders have told Bloomberg they believe a comprehensive U.S.-Iran deal could take six months.
Ships have to actually move. The Iran announcement declared the Strait open via a coordinated route. It is not yet clear whether that involves Iranian tolls, which the EU has called a dangerous precedent. Maersk, CMA CGM and Hapag-Lloyd suspended Hormuz transits weeks ago. They will not reverse course until they have confidence that vessels are safe and insurance is manageable.
Middle Eastern refinery restart timelines matter more than crude price. Nearly 3 million bpd of refining capacity shut in the region. Some facilities were physically damaged. The IEA flagged infrastructure damage as a key constraint on recovery even in its base case scenario. Product scarcity could persist well past the point at which crude flows normalize.
Venezuelan crude relationships do not disappear. The feedstock diversification Gulf Coast operators built over the past seven weeks stays in place. Valero's relationships with Chevron and PDVSA, and the direct agreements Phillips 66 and Citgo were building, continue to provide a cost advantage on the heavy end of the feedstock slate regardless of what happens with the Strait.
The operators who navigated the past seven weeks most effectively ran hard, diversified their feedstock mix and moved product to export markets before competitors could. The ones who navigate the next several weeks most effectively will watch the physical market, not just the headlines, and adjust run rate and product slate as the margin environment evolves in real time.
BIC Magazine has been covering this story since the conflict began. Read our earlier coverage on what the Strait of Hormuz crisis means for Gulf Coast refiners and LNG exporters, the IEA's record 400 million barrel reserve release, and key takeaways from the AFPM 2026 annual meeting on how Gulf Coast operators are positioning for the months ahead.
