Marathon Petroleum stock fell over 3% as a proposed U. diesel export ban and a Jefferies downgrade weighed on the company.
On September 22, 2026 Marathon Petroleum’s (NYSE: MPC) shares dropped more than 3% after two key developments. A White House proposal aimed at lowering diesel prices by potentially banning U.S. diesel exports and a downgrade by Jefferies both contributed to the decline.
Treasury Secretary Scott Bessent said the Trump administration is "mulling" a ban on diesel exports, describing it as a proposal still under examination for feasibility and whether a full or partial ban would work.
Jefferies analyst Lloyd Byrne downgraded Marathon from a buy to a hold, setting a price target of $413 per share. He cited that the current price and valuation are consistent with historical levels but warned of potential consumer pull‑back due to rising diesel prices.
Marathon is a major U.S. diesel producer, with diesel and jet fuel comprising the bulk of its Gulf Coast export volume, meaning any export restriction could negatively affect its operations. The likelihood and timing of an export ban remain uncertain.