The women's underwear market runs on strong opinions. Women love some brands fiercely and reject others completely. Scroll through Reddit and you'll see the same names come up over and over: Aerie, SkIMS, ThirdLove, Victoria's Secret, Commando. Each one comes with detailed reasons.

For OEM manufacturers, this matters. The brands winning have specific, provable reasons. The brands losing have equally specific reasons. Here's what the competitive landscape actually looks like.