Published by Global Banking & Finance Review®
Posted on March 6, 2026
3 min readLast updated: April 1, 2026
Add as preferred source on GoogleU.S. Gulf Coast heavy crudes, notably Mars sour, jumped to record premiums over WTI—highest since April 2020—as Iran-induced Strait of Hormuz disruptions tipped buyers toward U.S. heavies, while Brent rose to its loftiest level since October 2023 amid supply fears.
(Corrects source in paragraph 7 in March 6 story)
By Siddharth Cavale
NEW YORK, March 6 (Reuters) - U.S. Gulf Coast heavy grades continued to surge on Friday as the Iran conflict spurred several Middle Eastern producers of heavy crude to curtail production and drove buyers to scoop up U.S. barrels.
Prices of Mars sour crude, the flagship crude produced in the U.S. Gulf of Mexico and favored by refiners globally, traded at a $11 premium to U.S. benchmark West Texas Intermediate (WTI) crude on Friday, brokers said. That was the highest since April 2020, and up $4 from Thursday.
Just a week ago it traded at a premium of $1.50.
Other heavy grades such as the Heavy Louisiana Sweet and the West Texas Sour also rose.
Benchmark crude oil prices have surged since the initial attacks last week, with Brent crude settling at $92.69 a barrel, its highest level since October 2023 on Friday.
The effective closure of the Strait of Hormuz has forced several countries, including Iraq, to curb output. The strait is a key route for medium and heavy sour crude from the Persian Gulf, and those flows are now largely cut off. Additional production cuts announced in Kuwait on Friday also helped lift Mars prices, a trader said.
“Refiners that rely on these grades will need to find similar, or roughly similar, alternatives to replace the lost barrels, so Mars and other U.S. Gulf sour heavies and mediums are natural substitutes and are getting bid up aggressively,” said Matthew Lewis, founder of Plainview Energy Analytics, adding that buyers, especially in Asia, are scrambling for more of these medium and heavy crude barrels.
"This time of year also marks the shift from winter into driving season, when demand typically rises across all crude grades," said Tim Snyder, chief economist at Matador Economics, adding that ultimately the supply disruption caused by war was driving prices.
"In the short term we will continue to see these grades rise until we see the Strait of Hormuz open up," Snyder said.
(Reporting by Siddharth Cavale in New York and Georgina McCartney in Houston; Editing by David Gregorio)
U.S. Gulf oil prices surged due to the Iran conflict, which led Middle Eastern producers to cut heavy crude output, boosting demand for U.S. grades.
Mars sour crude is trading at an $11 premium to U.S. benchmark West Texas Intermediate, the highest since April 2020.
The closure effectively halted flows of medium and heavy sour crude from the Persian Gulf, forcing buyers to seek alternatives like U.S. Gulf crude.
Buyers, especially in Asia, are scrambling for more U.S. medium and heavy crude barrels amid supply disruptions.
Prices are expected to stay elevated until the Strait of Hormuz fully reopens and Middle Eastern supply resumes.
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