Today marks Amazon’s third annual Prime Day, and in addition to raking in an expected $1 billion, the e-commerce mammoth is promoting its in-house fashion brands.

While many luxury retailers have maintained a fairly tumultuous relationship with Amazon, the retailer has expanded its private labels like womenswear brands Lark & Ro, Ella Moon and Paris Sunday and menswear line Buttoned Down. Each is available only  to Prime members. On Prime Day, Amazon introduces new deals every five minutes over the course of 30 hours, beginning on July 10 at 9 p.m. EST.

A representative for Amazon wouldn’t share which brands are participating prior to the start of Prime Day, but she said that Amazon brands would have 30-50 percent discounts. For brands that currently sell through Amazon Fashion — including Calvin Klein, Kate Spade, and Levi’s — Prime Day raises a conundrum; high discounts put them at risk for brand dilution.

“Given Amazon’s recent efforts to further showcase its foray into fashion, we believe there will be some sort of spotlight shining on the [soft goods] selections, whether it’s additional deals, a specific fashion shop dedicated to these deals, a spotlight on new private label products, or even a cool promotion to incentivize more customers to try Prime Wardrobe, its new try-before-you-buy service,” said Elaine Kwon, founder of e-commerce management firm Kwontified and former head of the luxury division at Amazon Fashion.

While an increasing number of consumers are turning to Amazon for their apparel needs, data shows it continues to be overshadowed by other brands as the preferred platform for style. According to a report by Fung Global Retail & Technology, Amazon womenswear customers have doubled in the last four years: 23.2 percent of Amazon customers have purchased apparel from the platform in the last three months, compared to 14.5 percent three years ago. However, only 1.9 percent viewed Amazon as its go-to source for fashion, instead looking to retailers like Kohl’s, Walmart and Macy’s, the study found.

To stay competitive, these top retailers started announcing large discounts of their own leading into Prime Day. “These deals indicate the impact of Prime Day will be seen and felt everywhere, and not just on,” Ohad Hagai, vice president of marketing at analytics firm Feedvisor, told Retail Dive.