A Shock in the World’s Busiest Oil Corridor

Global crude markets have swung sharply over the past two months, and the story behind the swing is geography as much as it is economics. After Washington and Tehran signed a memorandum of understanding in June, Brent crude briefly slipped toward $69 a barrel by early July, reflecting hopes that tensions in the Gulf were easing. That calm proved short-lived. Renewed attacks on tankers moving through the Strait of Hormuz reignited fear in the market, and by July 23, Brent had rocketed to roughly $105 a barrel, a swing of more than 50 per cent in three weeks.

The Strait of Hormuz is not just another shipping lane; it is the single busiest chokepoint for seaborne crude and petroleum liquids in the world. Flows through it collapsed from an average of about 21.6 million barrels per day in the final quarter of 2025 to roughly 4.9 million barrels per day in the second quarter of 2026, once the conflict intensified. Compounding the disruption, a fresh threat has emerged against tankers using the Bab el-Mandeb Strait, the corridor Saudi Arabia has increasingly relied on to reroute its exports away from Hormuz. Volumes through Bab el-Mandeb had climbed to around 8.1 million barrels per day in the second quarter, up from 5.4 million barrels per day at the end of 2025, as Saudi Arabia shifted crude to its East–West pipeline and the Red Sea port of Yanbu. With that alternate route now also under threat, producers are left with costlier, slower, and lower-capacity options such as the Suez Canal and the Sumed pipeline.

Since then, prices have stayed firm: Brent climbed from around $79 per barrels on August 4 to nearly $89 per barrels by August 12, before easing slightly to $87.27 per barrels on August 13, with WTI tracking a similar path near $81.50 per barrels, signalling markets remain on edge even as the initial spike fades.

Shut-in Barrels and a Slow Road Back

The practical consequence has been a wave of production shut-ins across Gulf producers. Output losses are estimated to have averaged 5.5 million barrels per day in July, with Saudi Arabia, Iraq, and Kuwait among the hardest hit. Forecasts suggest curtailments will deepen further in August before beginning to ease in September, assuming shipping lanes gradually reopen. On current assumptions, a broad return to pre-conflict production and trade patterns is not expected until early 2027, and some Gulf producers may never fully recover their prior output levels within the forecast window.

Table: Brent Crude Oil Forecast

The above chart illustrates how shut-in volumes are distributed by country and how they are expected to evolve between June and July.

Inventories Draining, Prices Staying Elevated

The scale of the supply loss has forced a rapid drawdown in global oil stocks. Inventories are estimated to have fallen by roughly 4.2 million barrels per day in the second quarter, with an additional draw of about 3.8 million barrels per day expected in the third quarter. That inventory squeeze underpins an upward revision to the price outlook: Brent is now projected to average close to $85 a barrel in the third quarter, roughly $11 higher than the prior month’s projection. As shipping traffic normalises and curtailed output is restored, prices are expected to soften to an average of about $78 a barrel by the fourth quarter, before easing further to around $69 a barrel through 2027 as inventories rebuild.

Crude Oil Costs Cascade into the Petrochemical Chain

Crude price shocks rarely stay confined to the wellhead they move quickly through refining and into the petrochemical value chain, and the past several weeks have made that transmission unusually visible. Naphtha, the primary feedstock for steam crackers across Asia and Europe, has tracked crude closely. Cargoes landing in the Far East climbed from roughly $558 per kilogram in mid-January to more than $1,000 per kilogram by late July, before easing modestly to the $850–860 range by month-end. European naphtha followed a comparatively muted path, rising from around $511 to the low $700s, a smaller percentage move that highlights how regional supply balances and freight economics can decouple even closely linked markets during periods of stress.

Downstream of the cracker, olefin markets absorbed the shock directly. Ethylene prices in North Asia moved from the $735 range in mid-January to above $1,000 per tonne by late July, while European and US Gulf Coast values, though starting from a lower base, posted comparable percentage gains. Propylene followed a similar trajectory: Chinese and European values pushed toward $1.03–$1.22 per kilogram by early August, even as US Gulf Coast propylene eased slightly on the back of regional supply dynamics.

Aromatics have been no exception. Benzene, a bellwether for both fuel blending and downstream styrenics demand, jumped from roughly $743–889 per tonne across major hubs in mid-January to a peak above $1,370 per tonne in Rotterdam by late July, before retreating to the $1,240 range. Acrylonitrile, a smaller but strategically important intermediate for fibres, resins, and engineering plastics, moved in a narrower band, largely because contract-linked pricing in several regions cushioned the volatility that spot-exposed markets like naphtha and benzene experienced more fully.

What this Means for Downstream Companies

For refiners, olefin producers, and specialty chemical manufacturers, the past two months underscore a familiar but intensified lesson: feedstock volatility compresses margins faster than pricing teams can adjust contracts. Naphtha-based crackers in Asia, already operating on thinner spreads than their integrated Middle Eastern counterparts, have seen input costs roughly double at the peak, squeezing margins even where finished polymer and derivative prices have risen in step.

Several implications stand out for companies operating across this value chain:

Procurement teams should expect continued volatility through the third quarter, given that global inventories are still being drawn down and shipping through the Strait of Hormuz remains constrained. Locking in term contracts or diversifying feedstock sourcing away from Hormuz-exposed cargoes may help smooth exposure.

Regional price divergence creates arbitrage and risk simultaneously. The gap between Asian and European naphtha and benzene values, for instance, reflects freight bottlenecks and rerouting costs that are unlikely to normalise until Gulf shipping stabilises.

Margin recovery is likely to lag price relief. Even as crude and naphtha are forecast to ease toward the fourth quarter and into 2027, downstream contract resets typically trail spot movements by weeks to months, meaning margin pressure could persist even after headline oil prices stabilise.

Producers with flexible feedstock slates, able to shift between naphtha, LPG, and ethane, are better positioned to manage this kind of shock than single-feedstock crackers.