Why Victoria's Secret chooses to miss out on a multi-billion dollar opportunity

Victoria's Secret is notorious for not selling to plus size women.

Women have taken to Change.org to launch petitions, begging the lingerie company to sell larger sizes.

The company does not sell above a size XL (16) or above a DDD bra. Meanwhile, the average woman is a size 14 and 65% of women are considered plus sized - and according to research firm NPD Group, the industry is worth $17.5 billion.

"My money and my credit are good enough for them, but the fact that I can only buy items like perfume, lotion, and body spray sends the message that my body is not," Dana Drew wrote last year. "Every year I watch the Angel fashion show and would love to purchase the items I see on my screen but can't because Victoria's Secret doesn't sell plus sizes."

But the reason the brand omits larger sizes from its stores might not be for a cruel reason at all. It just might have to do with the way that bigger bras are constructed; they're made differently from their smaller counterparts.

"The biggest misconception [in the lingerie industry] is, I think, what goes into producing and designing lingerie," Cora Harrington, lingerie expert and Editor-in-Chief of The Lingerie Addict, said to Business Insider, "especially when you get to higher sizes. I think it's great there's been more vocal demand for larger cup sizes and more vocal demand for plus size, but what a lot of people may not realize ... is that each size grouping basically requires a different factory and a different set of patterns."

Though this doesn't necessarily address the absence of larger underwear, that does means that a G cup might not be made where a B cup is made.

This problem is actually a part of a major reason why plus size apparel is not sold by many mainstream retailers.

Plus size apparel requires a different pattern, and many budding designers are not taught how to design for these sizes when they're in school, as model Melissa Aronson (professionally known as Emme) told Business Insider in July.

Aronson launched a program at Syracuse University called Fashion Without Limit to fill in a huge hole in fashion's education system.

Bras require extreme specificity and expertise, according to Harrington.

"But in terms of engineering and skillset, intimates is the most demanding and technical niche in the fashion industry," Harrington said, adding that when you're one millimeter off, it can make a total difference.

And because of the structural demands of larger bras, some stereotypically "sexy" looks might not work for bigger bra sizes.

A "flimsy laced triangle bralette in a J cup," probably won't work, Harrington explained.

Of course, that doesn't mean that women who need bigger cups need to be completely in the dark and without sexy lingerie; Harrington has pointed to Amazon as a place that stocks larger bras and can therefore be a reliable alternative for curvier women who maybe can't find their bra size in traditional brick-and-mortar stores.

Victoria's Secret did not immediately respond to Business Insider's request for a comment.