The US base oil margin environment weakened in 2025, particularly compared with competing fuels, because of weaker base oil and lubricant demand.
The premium for Argus US domestic spot Group II N100 to competing fuel US Gulf coast diesel averaged 87¢/USG in 2025, down from 98¢/USG in 2024.
Refiners typically direct more vacuum gas oil (VGO) toward fuel markets when margins outweigh base oils. When base oil margins are firmer than fuels, base oil output increases.
The premium for Argus US domestic spot Group II N100 to feedstock low-sulphur VGO was flat year over year at $1.22/USG.
Group II N100 supplies were tighter in 2025 than 2024 because one key refiner adjusted its yields to increase its quality of N100, while another experienced consistent production issues throughout 2025.
Margins over VGO reached their highest in early May at $1.44/USG and fell to their lowest at 96¢/USG in late January.
Available re-refined Group II light grades also put downward pressure on virgin N100 prices, even when virgin N100 supplies were less available. This is because re-refined Group II/II+ volumes were at a discount to virgin grades throughout the year.
The persistent premium for base oils over competing fuels kept refiners prioritizing base oil output, even as base oil prices fell because of oversupply.
The average Argus US domestic spot Group II N100 spot price declined by 23¢/USG to $3.09/USG in 2025, compared with the 2024 average price of $3.32/USG, largely because of weaker demand. Margins for N100 over diesel reached their highest in early May at $1.09/USG, and fell to their lowest in late November at 48¢/USG.
Other base oil grades also experienced lower prices in 2025 compared with 2024, against because of weaker demand and increased surplus availability.
The average Argus US domestic spot Group II N220 price was $2.79/USG in 2025, down by 56¢/USG from the 2024 average price.
The Group II N220 grade was the most available grade throughout 2025 because of weak demand from the trucking and agricultural sectors.

