Every big box retailer should be terrified by this one chart

Big box retailers got hammered in the market on Wednesday, after Macy's reported dismal earnings.

That followed news of Amazon's stock reaching an all-time high, underscoring the more secular shift we've been seeing in online shopping.

But the bullcase for Amazon and the broader e-commerce market shouldn't stop there.

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As this chart by the financial research firm Pacific Crest shows, e-commerce is still only a tiny part of the overall retail industry, representing a mere 7.2% penetration rate. That means on average only 7 out of 100 retail customers are buying online.

In other words, there's a massive opportunity for online retailers, most notably Amazon, which has driven more than half of all US e-commerce growth last year, to win more share and generate more revenue.

Pacific Crest

The scarier part is that Amazon only gets about 25% of its total retail revenue from books and media, the most saturated e-commerce category. The rest of its sales comes from things like apparel, electronics, and home furnishings, categories that still remain vastly underserved, according to Pacific Crest's chart. Plus, Amazon's non-media sales is growing at a 30% clip year-over-year.

Perhaps, that explains why Cowen & Co. predicts Amazon will replace Macy's as the largest retailer in the US by next year.

Disclosure: Jeff Bezos is an investor in Business Insider through hispersonal investment company Bezos Expeditions.