Traders have made almost $1 billion betting against Under Armour this year

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• Under Armour short sellers have made almost $1 billion in 2017 betting against the stock, which had fallen 54% year-to-date through Tuesday.
• The company cut its full-year 2017 guidance as part of a disappointing third-quarter earnings report.

One of the safest bets in the flailing retail sector this year has been to short the worst-performing companies.

Under Armour has fit that strategy to a tee, and Tuesday's disastrous earnings report further fattened the bank accounts of traders betting against it.

Amid the company's 22% single-day drop, short sellers reaped a whopping $251 million in mark-to-market profits, according to data compiled by the financial analytics firm S3 Partners. That brings their total windfall to almost $1 billion this year as the stock has plunged 54%.

The damage on Tuesday came after Under Armour slashed its sales and earnings outlooks for the rest of the year. That news was followed by a chorus of analysts lamenting the decline of the once-promising brand, with Neil Saunders of GlobalData Retail going as far as to say the company's "days of glory" are "over."

You could argue the writing has been on the wall for months for Under Armour, which received unfavorable feedback in Piper Jaffary's recent Taking Stock of Teens survey, and launched a restructuring plan back in August.

It remains to be seen just how far Under Armour's stock can slide. After all, it's entirely possible that value investors will see an opportunity in the shares at the company's current lower valuations.

Still, it's clear Under Armour has its work cut out for it in terms of reclaiming lost market share. Until then, short sellers will continue laughing all the way to the bank.

Markets Insider