You've probably noticed that many apparel retailers are dumping their merchandise at steep discounts, shuttering their stores, or simply disappearing. Several major retailers -- including Aeropostale, The Limited, and American Apparel -- all filed for bankruptcy over the past year.

To understand what happened, let's look at the comparable-store sales (or "comps") growth of several major apparel retailers in 2016. Comps growth measures the year-over-year sales growth of stores open for at least year, which gives us an idea of how well their maturing stores are holding up.

Chart showing comparable-store sales trends at leading retailers

Data source: Company quarterly reports. Chart by author.

As this chart illustrates, many apparel retailers are struggling to post single-digit comps growth. This is mainly attributed to two key factors. First, fast-fashion retailers like H&M, Zara, and Forever 21 are rotating their products faster and selling them at lower price tags. Second, stiff competition from e-tailers is causing mall traffic to plummet.

Apparel retailers are trying to counter those declines by closing stores, mimicking fast-fashion strategies like rapid product rotation and analytics-driven design choices, and investing heavily in e-commerce channels. Several companies are also expanding smaller growth brands, like American Eagle Outfitters' (AEO -1.82%) Aerie and Tailgate, to offset weaker growth at their older core brands.

Many apparel stocks now have low valuations and high dividend yields due to the industrywide sell-off, but investors should exercise caution. This industry will likely remain a perilous minefield until more weak players are driven from the market.

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