Houston: The ongoing Iran conflict has created a competitive advantage for oil refiners along the US Gulf Coast, as rising tanker freight rates and insurance costs make crude imports more expensive for Asian competitors. The disruption to international shipping has widened discounts on heavy crude grades from Canada, allowing American refiners to secure relatively cheaper feedstock and strengthen their refining margins.

The Strait of Hormuz, a critical shipping route that carried around one-fifth of global oil and liquefied natural gas supplies before the conflict, has faced significant security-related disruptions. Longer shipping routes, tanker availability concerns and higher war-risk insurance premiums have increased the cost of transporting crude oil.

US Gulf Coast refiners are comparatively better positioned because they can source substantial quantities of heavy crude from nearby suppliers, including Canada and Venezuela. Asian refiners, on the other hand, often depend on seaborne imports and face higher transportation expenses when sourcing similar grades.

The changing market conditions have helped US refiners report stronger financial results, with industry executives indicating that the favourable conditions could continue into 2027.

Strait of Hormuz disruption pushes up shipping costs

The Iran conflict has significantly affected the economics of international oil transportation. Security threats around the Strait of Hormuz have disrupted tanker movements, forcing shipping companies and oil traders to account for longer voyages and increased insurance premiums.

The waterway is one of the world’s most important energy transit routes. Disruptions in the region can affect crude oil and liquefied natural gas supplies moving between major producers and international markets.

The impact is particularly significant for Asian refiners, which rely heavily on imported crude. When vessels face higher insurance premiums and longer journeys, the additional expenses increase the delivered cost of oil.

Freight rates have also increased sharply on routes connecting the US Gulf Coast with Asian markets. Valero Energy executive Randy Hawkins said transporting crude from the US Gulf Coast to Asia now costs approximately $30 to $35 per barrel, compared with around $5 a barrel a year earlier.

The rise in transportation expenses has changed the relative attractiveness of crude supplies from different regions, giving refiners with access to nearby resources a significant advantage.

Canadian heavy crude becomes cheaper for US refiners

One of the major beneficiaries of the changing market conditions is the US Gulf Coast refining sector. Refineries in the region are equipped to process heavier crude grades, including Western Canadian Select (WCS).

More than 70% of the Gulf Coast’s refining capacity is configured to handle heavier crude. This gives refiners the flexibility to use supplies from Canada and Venezuela rather than depending entirely on oil transported through longer international routes.

Western Canadian Select generally trades at a discount to the US benchmark West Texas Intermediate (WTI). However, the difference between the two grades has widened as transportation costs and market disruptions have affected crude trading patterns.

The wider discount reduces the cost of acquiring feedstock for refiners capable of processing heavy crude. This can improve their profitability, particularly when selling prices for refined products remain strong.

The advantage is not simply a result of lower crude prices. It also reflects the geographical position of US Gulf Coast refineries and their ability to access nearby supplies without facing the same shipping risks as some Asian competitors.

Phillips 66 estimates significant gains from wider discounts

The widening price difference between Canadian heavy crude and US benchmark oil has important financial implications for major refiners.

Phillips 66 executive Brian Mandell said every $1 increase in the WCS-WTI price differential could be worth approximately $140 million to the company.

This illustrates how relatively small changes in crude price differences can have a substantial impact on refining businesses that process large volumes of oil.

Valero executives have also highlighted the advantages created by higher freight costs. Chief operating officer Gary Simmons said expensive shipping has strengthened the company’s competitive position in Latin American markets, where it competes with fuel supplies from Europe.

Higher transportation expenses can make it more difficult for distant suppliers to compete in these markets. US refiners with access to domestic and nearby crude supplies may therefore benefit from their geographical advantage.

The companies are also benefiting from stronger fuel margins. According to oil and tanker market analyst Delia He of Arrow Shipping, the improvement in diesel margins has more than compensated for additional freight expenses in the current market environment.

Advance tanker contracts protect major refiners

The impact of higher shipping rates has not been equal across the refining industry. Companies that secured vessels through long-term charter arrangements before the conflict have been better protected from the increase in spot freight prices.

Phillips 66 said it had secured more than 40 time-chartered vessels before the conflict began. These vessels cover approximately 40% of the company’s asset-based shipping requirements.

Valero, PBF, Marathon Petroleum and Canada’s Suncor also secured chartered fleets before the disruption intensified.

Advance shipping arrangements can provide greater cost certainty and reduce exposure to sudden increases in tanker rates. They also help refiners maintain reliable access to transportation capacity when vessels become more expensive or difficult to secure.

However, companies that depend more heavily on the spot market remain exposed to volatile freight rates and changing insurance costs. The availability of vessels and the security situation around major shipping routes will therefore remain important factors in determining refining profitability.

US refining margins more than double

The favourable crude supply conditions have coincided with a strong improvement in US refining margins.

US refining margins more than doubled in the third quarter, according to the Reuters report. The combination of discounted heavy crude, stronger fuel margins and access to nearby supplies has supported the financial performance of Gulf Coast refiners.

The development is particularly important for companies that have invested in facilities designed to process heavier grades of crude. These refineries can benefit when heavy oil becomes cheaper relative to lighter benchmark grades.

The advantage also demonstrates how geopolitical developments can create different outcomes for businesses operating in the same global industry. While Asian refiners face higher import and transportation costs, some American refiners are benefiting from wider crude discounts and stronger product margins.

Nevertheless, the benefits are not guaranteed to continue indefinitely. A reduction in shipping risks, changes in crude supply or weaker demand for refined fuels could alter the economics of the market.

Refiners expect favourable conditions to continue into 2027

Several US refining companies expect the current market conditions to remain supportive in the coming months.

Marathon Petroleum expects to process record volumes of Canadian heavy crude in the fourth quarter. Its chief executive, Maryann Mannen, has indicated that refining margins could remain elevated through at least the middle of 2027.

HF Sinclair has also indicated that wider crude price differentials could persist through the near term and potentially into 2027.

These expectations suggest that refiners are preparing to take advantage of the current market environment for an extended period. However, the outlook remains closely linked to developments in the Iran conflict, tanker availability, insurance premiums and international fuel demand.

For Asian refiners, sustained high shipping costs could mean continued pressure on procurement expenses and competitiveness. Companies may need to reassess crude sourcing strategies and transportation arrangements to manage the changing economics.

Global oil market faces changing competitive dynamics

The Iran conflict has demonstrated how disruption in a major shipping corridor can reshape competition across the global refining industry.

US Gulf Coast refiners are benefiting from access to nearby Canadian and Venezuelan heavy crude, while higher freight and insurance expenses are increasing the cost burden for several Asian competitors.

The situation also highlights the importance of securing reliable shipping capacity and diversifying crude supplies. Refiners that can manage transportation risks and maintain access to competitively priced feedstock are better positioned to protect their margins.

For now, the US Gulf Coast enjoys a significant advantage from the widening discounts on heavy crude. Whether that advantage lasts into 2027 will depend largely on the security of international shipping routes and the direction of global oil prices and refining margins.