Underwire Bikini Market Report: Sales Volume, Market Share, Leading Brands & Market Trends

CUPSHE is the best-performing underwire bikini brand in July 2026, moving 1,200 units across 3 ASINs for 27.9% of Top 10 volume. SherryDC follows with 800 units (18.6%), ahead of Aqua Eve on 600 units (14.0%).

With 8 brands splitting the Top 10 and 60.5% 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 $26.99 to $37.99, 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: B0839G2GGM booked 400 units at $25.99. On the growth side, B0DRSWBCC3 leads positive momentum with ▲ 100.0% MoM growth on 200 units, with B0F9Y27MXK close behind at ▲ 100.0% MoM on 200 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already changed hands — an incumbent gave up its place to make room, so any competitive set drawn up a month ago is now out of date.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.