Christine Hunsicker saw opportunity in the $120 billion women's apparel industry: One-third of U.S. women wear plus-size clothing, but they represent under a fifth of women's apparel spending. So in 2011, she launched Gwynnie Bee, a plus-size, everyday-clothing rental service. The hard part was getting designers to make clothes for her.

--As told to Zoë Henry

The first brands we rented out were already making plus-size clothing. Coming into 2014, though, we were massively short on inventory. The only way to meet demand was to design a collection ourselves. It wasn't great. We were trying to work with natural fiber, but it looked like we were renting out terry cloth bathrobes. We rushed the patterns, so the proportions were off in sizes above and below the median size of 12.

Once we understood that design is a real discipline, we brought on a patternmaker who had worked for Ralph Lauren in its plus division. We also started involving customers in the fitting process by sending out dresses to members of all different shapes and sizes and getting their feedback. The good thing about the rental market is that you learn very quickly, because people are constantly trying on the clothing.

For the traditional designers, the biggest fear of getting into this market is, "My stuff is not going to fit; it's not going to work," because they've never built clothes for our type of consumer. (Creating plus-size patterns doesn't involve just making a medium-size pattern proportionally bigger. Aspects of a pattern change completely in larger sizes.) So we showed them the expertise we'd developed in upsizing patterns. We offered to complete full, plus-size patterns for them to use in manufacturing. "We will do this for you, or we'll do this with you," we said. Seven of them took us up on the offer.

Today, we have an entire team of designers and patternmakers on staff. We work with more than 190 brands and have rented out three million boxes of clothing, mostly in the past year. We've raised more than $100 million in venture capital.

We stay away from working with certain brands that have publicly said they disdain this plus-size customer. But there are boutique brands out there that are looking to really build their businesses, and want their clothing to make women feel good. Making women feel good and confident about themselves is tied to how I feel as a feminist. Women should not allow the "other" to make them feel less than what they are.