Spot freight on the US Gulf Coast has spiked to Worldscale 287 as the list of available medium-range product tankers emptied from 33 ships to six in four days ahead of a possible US diesel export ban. US diesel prices have slipped roughly 5 cents in the past week to $6.45 a gallon, below the record $6.53 set last week, while global diesel prices jumped more than 20 cents a gallon overnight. The Houston-Rotterdam diesel arbitrage remains positive through October 2027, at $10.65 a metric ton a year out.

Goldman Sachs estimates each week of a ban would initially cut US retail diesel prices about 25 cents a gallon, with the effects worsening the longer it lasts. Diesel and gasoline are produced together, so cutting diesel output would push gasoline up roughly 30 cents a gallon once storage fills. European wholesale diesel would rise about $3 a barrel each week, a move only partially offset by SPR releases, and global prices would still be higher after a ban lifts than without one because of lost US refinery output. Goldman recommends hedging through long European gasoline positions.

UK ministers have privately warned that Britain could face diesel shortages if Trump bans US diesel exports. UK Business Secretary Jonathan Reynolds has called a full ban a "significant concern" for Britain, which sources about one-sixth of its diesel from the US, though he stressed the country has a diverse fuel supply. The US has emerged as the world's supplier of last resort, with diesel exports hitting a weekly record near 2 million barrels a day last month as the Iran war and Ukrainian attacks on Russian refineries tighten world supply. Trump said Sunday he is still looking "very seriously" at a ban and "we may do it," while acknowledging it "can oftentimes lead to a little bit of an increase on gasoline for cars." Energy Secretary Chris Wright favors voluntary export limits, and Senator Ted Cruz has told refining industry leaders the White House assured them an outright ban would not happen.