Base oils are classified by the American Petroleum Institute (API) in 5 groups of increasing quality. Each higher quality group generally is higher cost to manufacture, or results in lower product yields, or both. APIs Group I, II, and III are mineral oils, whereas Groups IV and V are petrochemicals.
Since motor oil standards were upgraded to GF-6 on May 1, 2020, the price premium of light and medium Group III base oils over Group II base oils increased by 300% and 100% respectively, reflecting both an increase in demand and the higher cost associated with Group III base oil manufacturing. Light and Medium base oil will comprise about 33% and 21% of our plant production, respectively.
API Base Oil classification system by group number is shown next below as defined by Viscosity Index (VI), Saturates, and Sulfur.