President Donald Trump has directed the US Department of Justice to open an investigation into whether major oil companies are "gouging" consumers by keeping petrol prices elevated despite a sharp decline in global crude oil costs. In a social media post shortly after midnight on Wednesday, Trump said the big oil companies were "not dropping their price at the pump commensurate with the sharply lower prices they are paying for Oil," adding that crude prices were "dropping like a rock." The directive came as the national average petrol price stood at $3.906 per gallon, down more than 14 per cent from its May peak but still well above the $2.764 recorded in January, before the Iran conflict disrupted energy markets.

Viewed from Washington, the intervention reflects mounting political pressure on the White House over fuel costs ahead of November's midterm elections, in which Republicans are defending narrow congressional majorities. Trump's post did not name any specific companies, and neither the White House nor the Department of Justice immediately commented on whether a formal probe had been opened. Industry analysts in London and New York note that retail petrol prices are shaped by factors beyond crude costs, including refining margins, transportation, taxes and regional market conditions, which can delay the pass-through of lower feedstock prices. The president's accusation of gouging, they argue, may conflate a normal commercial lag with deliberate profiteering.

The gap between crude and pump prices has widened since the United States and Iran signed an interim memorandum of understanding last week, which included the reopening of the Strait of Hormuz — a chokepoint through which roughly one-fifth of global oil supplies transited before the war — and a temporary US sanctions waiver allowing Iran to sell oil on international markets. Crude benchmarks have fallen roughly 23 per cent from May highs and about 40 per cent from their March peak, yet petrol prices have declined more slowly. Iranian state media, reflecting Tehran's official narrative, described Trump's earlier military actions as "illegal tension-creating" and portrayed the price complaint as a consequence of his own policies. The interim deal remains fragile: US and Iranian officials have issued divergent statements on the status of negotiations, and core disputes over Iran's nuclear programme are unresolved.

The political sensitivity of petrol prices in the US is acute. Consumer frustration has been amplified by the war's inflationary impact, and Trump has previously insisted that fuel costs would drop sharply once hostilities ended. GasBuddy's head of petroleum analysis told Forbes that while the Hormuz reopening would bring relief within days, prices were unlikely to return to pre-war levels "for many months." The Department of Justice has not confirmed any investigation, and no companies have been identified for scrutiny. The dossier remains at the stage of a presidential instruction issued via social media, with no formal legal process yet under way.