General Motors Co. (GM) just had its worst day in over a year, and it's not hard to see why.

Diesel prices are at record highs and Treasury yields at their loftiest since 2007. Both circumstances are squeezing the trucks and SUVs that keep Detroit's lights on.

GM shares tumbled 5.2% Friday, putting the automaker on track for its worst session since July 2025.

The move erases Thursday's 3.6% advance and drags the automaker to levels last seen in late July. GM is down roughly 4% on the week, a second consecutive weekly loss.

Today, diesel hit record highs above $6.30 a gallon. Prices spiked after a drone strike damaged pumping stations on Saudi Arabia's East-West pipeline.

Financing costs are climbing in parallel: the 10-year Treasury yield touched 5.04% Wednesday, its highest since 2007, after the Federal Reserve raised rates for the first time since 2023.

Ford Motor Co. (F) fell 2.9% to $13.22, on track for its lowest close since May and a second straight negative week.