Designer Tanya Taylor was intent on extending her brand’s sizing range from 0-12 to 0-22. Thanks to customer data around demographics, shopping behavior and purchases, she also had the wherewithal to make it happen.

“What it’s all about is if, as a brand, you want to do it. For us, I needed to do it. I felt the frustration of the customer, but I also had the information about the customer that proved it was something we should be doing,” said Taylor. “If we had done this 15 years ago, we would be reliant on hearing Bergdorf tell us who our customer is. As a designer today, you have a lot more opportunity to follow the information you have and the instinct that you have about your customer. It’s empowering.”

Taylor introduced a capsule collection of eight items in the 14-22 size range in her pre-fall 2017 collection. The decision was sparked by a conversation Taylor had with “Saturday Night Live” star and plus-size actress Aidy Bryant, who reached out to the designer on Instagram. She loved her clothing’s bright patterns and prints, but Taylor didn’t offer her size. Taylor spoke to more women in the same size demographic before deciding to build the first capsule collection. Since that first collection, extended sizes have been introduced with every new season.

The plus-size collections are available through Rent the Runway, where the Tanya Taylor brand team closely monitors customer feedback on fit, as well as online plus-size fashion retailer 11 Honoré and the brand’s site. Right now, plus-size clothing represents about 15 percent of inventory on the Tanya Taylor e-commerce site, but 30 percent of sales. Taylor explains the outsize demand as a sign of plus-size shoppers’ lack of contemporary fashion options in the market.

“We took it slow to understand what it would look like for us, and it does feel like a different part of the business because it requires a different fit model, different cuts and a different understanding of fit,” said Taylor. “We’ve seen such growth from it, though, so we’re increasing our options to make it a more meaningful part of what we do.”

The opportunity for brands and retailers to cash in on this gap in the fashion industry is a sizable one: According to NPD Group, plus-size apparel is a $22 billion industry and is growing at a faster rate than other apparel categories, at 6 percent year-over-year. Piecemeal progress is being made in fashion: Other designers like Christian Siriano and Prabal Gurung have worked with partners including Ashley Graham and retailer Lane Bryant to reach this customer with a more fashion-forward selection. On the retail side, Nordstrom recently began working with brands to push them to expand their sizing options, basing new marketing, in-store and online initiatives around a more size-inclusive customer experience. Brands like Rebecca Taylor, Theory and Nike have opted in.

The push from brands like Tanya Taylor to offer more sizes calls into question the excuses that brands with limited sizing have long stood by, including a lack of customer demand and resources. While Taylor said that, in some ways, adding new sizes felt like starting a new brand, the investment was only an upfront cost: Once she got started, it didn’t cost the brand any more to keep going. Investment and resources revolved around adjusting to new tools in design and manufacturing; it doesn’t work for a designer to simply scale up existing sizes. New fit models and an understanding of fit had to be adopted, while factories had to be pushed to accommodate for different sized dress forms. Taylor had to learn more about the size variability in plus-size fashion, as well as what styles and cuts this customer prefers. She started with dresses, and has since expanded the collections to include tops and bottoms.

“It involved work, and it cost a lot to start the process, but once you do start it, it’s seamless,” said Taylor. “Financially, you can look at it and say it’s a risky investment, but it’s really not. It pays off.”

To make more of her designs in extended sizes and to make the collections a more equal part of the business, Taylor said she plans to work on pushing retail partners like Saks and Shopbop to invest in the inventory buys in sizes above a 12. As the power dynamics and ownership of the customer insight continues to shift between wholesale and designer, she sees it as more of a possibility.

“More designers are coming forward and saying this is important. Designers used to have to listen to wholesalers about what they should be doing, and they followed the demand of wholesale, and I feel like that’s flipped,” she said. “Wholesale is now looking to designers because designers have direct consumer information, as e-commerce is so important. Our partners now know that our confidence about a design or style is representative of our customer, and they can trust that because of our intel. That’s a big shift.”