Like any high school crush, this one was bound to fizzle, but the breakup was still tough—especially because millions of dollars were riding on this infatuation.
Teenage girls have dumped their longtime retail heartthrobs, and while the brands are trying to woo them back, the girls have picked up their trays and moved to another table. The question on investors' minds is whether this famously fickle demographic has moved on for good.
An anonymous report from Buzzfeed that women's clothing sales plummeted by nearly a third at once-vaunted teen retailer Abercrombie & Fitch is a symptom of a broader malaise in the sector, analysts say.
(Read more: Teens on what's hot for back-to-school)
Abercrombie and its rivals Aeropostale and American Eagle Outfitters all came in with poor results last month. Aeropostale and American Eagle both used the words "disappointing" in investor conferencecalls.
"We're not at all happy with our second quarter performance," American Eagle Outfitters CEO Robert Hanson told investors last month. He said that although most areas of the retailer's North American business came in below expectations, its women's business had the biggest miss.
Abercrombie wouldn't comment on the report that its women's sales had fallen by 30 percent, but CEO Mike Jeffries told investors last month the retailer had "ongoing weakness" in women's clothing, with knit tops a primary trouble spot.
"The reasons for the weak traffic we've seen in the U.S. are not entirely clear," he said. "Our best theory is that while consumers in general are feeling better about the overall economic environment, it is less the case for the young consumer."
(Related video: Back-to-school retail results)
Morningstar equity analyst Jaime Katz agreed, calling the sector's performance "exceptionally weak." Analysts had expected better numbers because labor and commodity costs had stabilized, and a cool summer was expected to jump-start back-to-school shopping, she said. That didn't happen.
One big reason is that fewer teens are working than in years past. Department of Labor data show that in July, typically the time of year when summer jobs boost youth employment, only about a third of teens age 16 to 19 worked.
"The employment-population ratio for youth has been in a rather steep decline since the beginning of the 1990s," plummeting even further in the Great Recession, acording to the Bureau of Labor Statistics.
And teens today have more places than ever to spend what money they have, said Barbara Wyckoff, an analyst with Credit Agricole Securities (USA) Inc. "Entertainment, downloads, food, gas. We think that clothes just aren't that important to teen customers anymore," she said via email.
Jeffries echoed this, telling analysts, "We believe youth spending has likely diverted to other categories."
Analysts say no single must-have trend captured teen girls' attention this year the way colored jeans did last year. "The teen uniform is jeans and T-shirts which has NOT changed in a long time. Without a major change in silhouette to drive incremental units, jeans are a 'replacement business' and we all know that old jeans are better than new jeans," Wyckoff said.
(Read more: Retailers resort to deep discounts)
Not a single teen in an August CNBC profile had begun shopping for back-to-school clothes. Analysts say some of this is just a timing shift; kids wait to see what their classmates are wearing before hitting the mall.
But some also said not having money to shop for clothes was holding them back. Teens interviewed by CNBC said full-priced merchandise at Abercrombie was too expensive, and passed over offerings like a simple sweatshirt from American Eagle with a $35 price tag. Analysts say this benefits cheap-chic brands like H&M and Uniqlo at the expense of traditional teen retailers.
When teens or their parents do spend, frugality remains a major factor. "It's becoming so much more price competitive," Katz said. "How do you justify buying $40 sweatpants? It becomes harder for parents to want to pay for it and harder for teens to want to pay for it."