Girls Underwear Size 12 Market Report: Sales Volume, Market Share, Leading Brands & Market Trends

Fruit of the Loom is the best-performing girls underwear size 12 brand in July 2026, moving 8,000 units across 3 ASINs for 36.4% of Top 10 volume. Finihen follows with 4,000 units (18.2%), ahead of Popular on 3,000 units (13.6%).

With 6 brands splitting the Top 10 and 68.2% 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 $14.99 to $23.99, 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: B0B2P633NW booked 1K units at $9.99, with ▲ 66.7% MoM change. On the growth side, B0G12V2N7J leads positive momentum with ▲ 400.0% MoM growth on 500 units, with B084DSQ8L2 close behind at ▲ 166.7% MoM on 800 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already changed hands — an incumbent gave up its place to make room, so any competitive set drawn up a month ago is now out of date.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.