The gap between Brent crude, the global oil benchmark, and WTI (U.S. crude benchmark) widened to almost $9 a barrel after President Donald Trump raised the possibility of restricting diesel exports. Brent stood at $100.88 a barrel on Thursday, while WTI was $91.89, leaving the spread about $1.40 wider than a day earlier and well above its normal $2-to-$5 range. The divergence reflects falling WTI rather than rising Brent: from Sept. 18 to Sept. 28, Brent gained $1.41 while WTI lost $7.70. A diesel export restriction could leave Gulf Coast refiners with excess product, reducing their incentive to operate at full capacity and weakening demand for U.S. crude. Analysts said markets were pricing the risk of a significant reduction in refinery runs, although the probability of an announced ban by Oct. 31 had fallen to 12% on Polymarket from 22% on Sept. 24.