Shares of Skechers (NYSE:SKX) have been in decline since its last quarterly report, despite the company's reporting rising sales. The stock of sports apparel companies Nike (NYSE:NKE) and Under Armour (NYSE:UA) (NYSE:UAA) are also in decline, but that seems more directly related to the fact that their sales are hitting the brakes. Meanwhile, Skechers reported a 16.9% increase in net sales for the second quarter. It looks like Skechers is getting unfairly lumped in with its competition.

SKX Chart

SKX data by YCharts

A tailwind coming to an end?

After years of strong growth, it looks like sales of athletic apparel are slowing down. The athleisure fashion movement -- wearing sports and gym gear for everyday use -- has become mainstream and while sales of all things performance-related are still going up, they aren't going up nearly as fast.

Whenever a sales slowdown is in the works, competition increases as the players fight over a dwindling market. Athleisure is far from dead, but that increased competition for the consumer is visible through things like increased advertising spending, discounting, and other promotional activity. Check out the short-term revenue trend at these three companies.

Revenue Growth (YOY)

Nike

Under Armour

Skechers

Fiscal year 2016

6.9%

21.8%

13.2%

Q1 2017

5%

6.6%

9.6%

Q2 2017

5.3%

8.7%

16.9%

YOY = year-over-year. Nike's fiscal year ends in the quarter of the calendar year. Data sources: Nike, Under Armour, and Skechers quarterly earnings results.

Skechers' competitive advantage

If athleisure isn't providing the same boost as in the past, what is Skechers doing differently than Nike and Under Armour? Part of the answer is that Skechers sells shoes and does a negligible amount in the clothing department, whereas for Nike and Under Armour, shoe sales are at 65% and 21% of the total, respectively. Apparel sales -- which are the top revenue-generator for Under Armour and the No. 2 category for Nike -- are dragging the numbers down. Though Skechers' top line is accelerating due to its pure shoe business, the stock is down anyway on a profit "miss" in its second quarter -- $0.38 a share versus management forecast of $0.42 to $0.47. However, even that miss is due to things the company is doing to keep business going strong.

Heavy investment in international expansion was the primary reason for the lower-than-expected profits. The company's goal is to achieve 50% of revenue derived from overseas, which it is on track to hit this year.

To that end, Skechers has been opening new retail locations in places like Germany, Chile, India, China, and Australia. New joint venture businesses have also been established for other key markets like South Korea and Japan. As a result, international retail and wholesale were up 28% and 18.6% in the last quarter, respectively.

A young woman wearing workout clothes and a pair of red Skechers shoes.

Image source: Skechers.

Skechers has also seen an uptick in its stateside business as of late. Several lines of new shoes aimed at work and casual comfort are winning with consumers. With U.S. athletic apparel sales appearing to peak, Skechers' existing lineup of cheaper athletic and casual shoes, as well as a focus on the work shoe category, puts it in an ideal spot to eat up market share. Domestic wholesale was up 6.4% in the last quarter, compared with a 4% increase in shoe sales at Nike and a 2.4% decrease at Under Armour.

Justly punished, but for the wrong reasons

Excluding the profit miss because of investment into its international business, Skechers has been enjoying success where its higher-profile competition is wavering. The stock is certainly a better value, too, and not just because of the higher top-line sales growth. The trailing-12-month price-to-earnings ratio currently sits at 17, compared with 21 and 39 for Nike and Under Armour, respectively.

Though it is getting punished along with athletic shoe companies, Skechers looks like a good buy after the pullback. Sales are accelerating once again, and shareholders should eventually be rewarded with higher profits as investments overseas begin to pay off.

Nicholas Rossolillo owns shares of Skechers. The Motley Fool owns shares of and recommends Nike, Skechers, Under Armour (A Shares), and Under Armour (C Shares). The Motley Fool has a disclosure policy.