US refiner Marathon Petroleum and the marketing arm of refiner Valero have filed separate lawsuits seeking refunds from the US administration's sweeping tariffs enacted last year.
The challenges are among hundreds filed by a variety of companies that are awaiting a ruling from the US Supreme Court in the coming weeks on the legality of the unilateral tariffs that President Donald Trump has imposed on imports from nearly all US trading partners by tapping emergency powers.
It is unclear what products the two refiners imported that were subject to the tariffs. Both companies also have midstream and logistics assets. In addition, retail outlets are largely owned and operated by independent contractors.
Valero and Marathon did not respond to Argus requests for details.
Petroleum products have been largely exempted from the US tariffs except for three days in March 2025 during which Trump imposed stiff tariffs on energy and other imports from Canada and Mexico but rescinded them after US stock market indexes fell and energy and auto industries pushed strongly against his policy. Trump subsequently signed executive orders that would exempt items covered by the US-Mexico-Canada (USMCA) free trade agreement from the new tariffs.
Valero Marketing and Supply "is an importer of record for foreign-origin merchandise imported into the United States" that "has been and continues to be subject to the tariffs imposed" by Trump executive orders issued last year, according to a document filed last month to the US Court of International Trade.
Valero asked the court to declare that the emergency tariff orders that Trump declared under the 1977 International Emergency Economic Powers Act (IEEPA) are unlawful and to order the US administration to issue refunds.
Marathon Petroleum and Marathon Petroleum Supply & Trading filed a similar suit, saying they "are importers of merchandise" into the US that are subject to the challenged duties, according to a court document filed in December to the US Court of International Trade.
Lower courts already ruled that Trump has acted illegally by placing emergency tariffs on most goods imported into the US. Previous presidents only used IEEPA to impose targeted economic sanctions.
The Supreme Court must address both the legality of IEEPA and, if it strikes down Trump's tariffs, decide how to refund the tariffs collected since March 2025. The Court of International Trade already ruled that all IEEPA tariffs must be refunded. Another court has ruled that only companies requesting a refund will get one.
The Supreme Court may make an altogether different decision on refunds, but US importers — including Valero and Marathon — appear to be hedging bets by explicitly asking for tariff refunds.
Ruling would cover most Trump tariffs
The Supreme Court ruling will address Trump's most extensive action — imposing tariffs of 10pc and higher since 5 April 2025 on nearly every US trading partner to address the "economic emergency" of persistent US trade deficits.
The Supreme Court's decision will also affect Trump's tariffs on Mexico, Canada and China, where he cited an economic emergency created by the three countries' alleged inaction to stop the flow of fentanyl drugs into the US.
The court's decision will not affect tariffs on US imports of steel, aluminum, cars and auto parts, which Trump imposed by citing well-tested legal trade authorities.
If the Supreme Court rules against Trump, the administration is prepared to impose a temporary 10pc tax on imports before rolling out more permanent measures, a senior White House adviser said last month.
Trump has warned that paying the tariffs back could take years to figure out if the Supreme Court rules against the administration.
"I just hope the Supreme Court does what's right for the country," Trump said on Fox Business on 9 February. His administration can come up with alternative tariff solutions if the Supreme Court strikes down IEEPA tariffs but "it won't be as beautiful as it is right now", Trump said.
