Def Fluid Market Report: Sales Volume, Market Share, Leading Brands & Market Trends

Valvoline is the best-performing def fluid brand in July 2026, moving 11,000 units across 2 ASINs for 49.3% of Top 10 volume. Archoil follows with 7,000 units (31.4%), ahead of Rislone on 1,600 units (7.2%).

With 5 brands splitting the Top 10 and 87.9% of volume sitting with three of them, this is a concentrated shelf — the leaders hold multiple listings or one very high-velocity ASIN, so a new entrant competes against established review moats rather than an open field. Average selling prices among the leaders run from $16.86 to $72.40, which frames the price band a competing listing has to justify.

Based on July 2026 data, this shortlist surfaces the two kinds of ASIN worth keeping an eye on — the ones that just broke into the Top 10, and the ones growing fastest month over month. Specifically, one ASIN forced its way in: B0CRSNDVHW booked 600 units at $12.99, with ▲ 0.0% MoM change. On the growth side, B07DLDZBS8 leads positive momentum with ▲ 100.0% MoM growth on 200 units, with B08L45WYNJ close behind at ▲ 100.0% MoM on 100 units.

The two signals carry different weight. A fresh entrant means share has already changed hands — an incumbent gave up its place to make room, so any competitive set drawn up a month ago is now out of date. A steep growth rate works as the earlier warning: it marks demand that is still compounding, usually a month or two before the ranking catches up to it.