The next time you visit J.C. Penney, you might notice some changes in its options for plus-size shoppers: The department store announced this week that it is introducing its first in-house plus-size brand, dubbed Boutique+, that will aim to deliver trendy pieces for millennial shoppers. And J.C. Penney also is spiffing up the presentation of its plus-size attire, adding to 200 of its stores an area dubbed “The Boutique” that it promises will feature sleek decor and the vibe of an independent, curated shop.

These moves by J.C. Penney might not exactly be industry-shaking, but they are the latest evidence that the retail world seems to be taking fresh notice that plus-sized shoppers are an underserved market. And, at a moment when apparel sales generally have been soft, leaving many brands eager to unlock new growth, they’re realizing that they might be leaving money on the table by not catering more to this group, especially its younger members.

Target made a similar calculus last year when it rolled out Ava & Viv, its own exclusive plus-size line. While the retailer had some workwear and evening clothes for plus-size women, the company believed that it was missing a major market opportunity by not having more casual plus-size pieces for style-conscious shoppers.

And Eloquii, the plus-size e-commerce shop, announced last week that it has raised a fresh $15 million in venture capital, an investment that appears to be a bet that the retailer will only continue to build on the 165 percent sales growth it delivered last year by selling fast-fashion gear.

While these lines are largely courting 20- and 30-somethings, new research shows there might be even more opportunity in merchandising plus-size pieces for an even younger crowd.

“Teens are reinvigorating the plus-size market,”  Marshal Cohen, chief retail analyst at NPD Group, said in a statement. “Today’s young consumers know what they want and won’t settle for less. This energy will turn up the volume at retail for the plus-size apparel market overall.”

Cohen’s analysis reflected a recent study by NPD Group of “special sizes,” a category that includes plus, petite and tall apparel. NPD found that the number of teenagers buying plus-size apparel has nearly doubled since 2012. The research also found that teens were more likely than other age groups to say “brands design plus-size clothing as an afterthought.”

These findings may help explain why still more retailers are looking to expand their plus-size assortments. Teen-centric retailer American Eagle Outfitters says it working toward offering extended sizes on its e-commerce site later this year. And department store chain Bon-Ton expects to roughly double the number of stores that carry its “young contemporary” plus-size line this spring.

For its bid to win over millennial plus-size shoppers, J.C. Penney has enlisted Ashley Nell Tipton, the “Project Runway” designer who claimed the show’s top prize by designing a plus-size runway collection — a first for the series.  Tipton is currently serving as a brand ambassador for Boutique+ and will be designing pieces for a fall and holiday collection. The retailer is promising that customers can expect trendy, ’70s-inspired pieces from the first collection, including fringe-bedecked tops and pleated skirts.

J.C. Penney’s play for the plus-size market is part of a broader effort by chief executive Marvin Ellison to reinvigorate a chain that has been on something of a roller coaster in recent years. Ellison has made it a key priority to build up J.C. Penney’s roster of exclusive brands to help differentiate it from competitors such as Kohl’s and Macy’s. The launch of Boutique+ appears to fit squarely within that mission.