Under Armour could have a new challenger in Amazon soon

Updated from 1:06 p.m.

Amazon (AMZN - Get Report) is planning to create its own line of workout clothing as it expands further into the private-label clothing business, according to several job postings on its site.

The Seattle-based company is seeking several senior brand managers of private brands for Amazon active apparel.

"The candidate will collaborate with leadership to build authentic activewear private label brands that have compelling and unique DNA and deliver amazing consumer valued innovation," one job posting says.

The posting also says the preferred candidate would have a "passion for sport, athletes and those living an active lifestyle" and established relationships in fashion and/or athletic apparel, supply chain or vendor communities.

The job postings were first reported by Re/code. An Amazon spokeswoman declined to comment to TheStreet

An athletic line from Amazon would put it in direct competition with the likes of Under Armour (UA - Get Report) , Nike (NKE - Get Report) and Lululemon Athletica (LULU - Get Report) . The U.S. activewear market, estimated at sales of $44 billion, has become crowded, according to NPD.

"There is a lot of noise in the activewear market right now, as more manufacturers are marketing products that originally weren't considered active or athletic apparel...This is especially having an impact on those more traditional manufacturers who have built a reputation around technical, athletic apparel," said Matt Powell, VP and sports industry analyst at NPD.

Amazon already has several of its own apparel brands, although not athletic, such as its line of men's shirts called "Buttoned Down" and "James & Erin" women's apparel.

The e-commerce giant also has a variety of other private-label products, such as speakers, pet supplies and batteries. Private-label brands are a way to boost profit margins.

A recent report from 1010data found that Amazon private-label brands are gaining market share from existing category leaders. The firm analyzed sales trends from September 2015 to August 2016 for three key online categories: batteries, speakers and baby wipes. 1010data said Amazon is heavily competing with category leaders and in certain cases even becoming the online category leader.

"No matter the market, the challenge for brands in an increasing number of categories is that Amazon is the top online channel. And Amazon is leveraging its dominance to sell their own private-label brands which compete with traditional suppliers," said Jed Alpert, senior VP of Marketing at 1010data.

Shares of Amazon.com are slightly higher at $756.11 in early afternoon trading.

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