U.S. average retail diesel prices climbed to $5.60 per gallon by mid-May, representing a 58.3% increase year-over-year and a $2.06 increase compared to May 2025, as outlined in the June 2026 Diesel Fuel Index from Magnus Technologies. The analysis also identified a $0.96 per gallon increase during the week of March 9, the largest single-week move recorded in the dataset.
"Fuel surcharges are meant to be a neutral pass-through," says Matt Cartwright, founder and CEO of Magnus Technologies. "In a volatile market, manual or infrequent updates create a gap between actual fuel costs and what gets charged, leaving carriers to absorb costs they were never meant to carry. The difference comes down to timing: aligning fuel cost recovery to real-time conditions instead of static assumptions."
Key takeaways:
· Diesel prices surged more than 40% in under two months in early 2026, exposing a widespread challenge across the freight industry. Many fuel surcharge programs rely on monthly or quarterly reset schedules that were unable to keep pace with rapidly changing market conditions, leaving carriers responsible for fuel costs that surcharges were intended to recover.
· The analysis found that a carrier operating under a typical monthly fuel surcharge reset schedule could experience approximately $168,000 in unrecovered fuel costs during the surge window, while quarterly reset structures could leave more than $400,000 unrecovered.
