Skechers(NYSE:SKX) stock soared to a new all-time high on Thursday after the company reported second-quarter earnings that surpassed analyst expectations. Conveniently, peer Under Armour (NYSE:UAA) also soared higher after accelerated growth, while Crocs (NASDAQ:CROX) traded higher for another reason. Nonetheless, with Skechers seeing gains of nearly 200% since 2013, is the stock still a buy at these levels relative to its peers?

A new and improved Skechers
Skechers has staged an absolutely incredible fundamental turnaround over the last year, which really jumped to a new level during the first six months of this year. So far, revenue has grown 21% and 37%, respectively, during the first and second quarters, with margins growing at an even faster rate. Moreover, in the second quarter alone, net income soared almost 400% year over year to $34.8 million.

Combined, the company has seen year-over-year revenue growth of 29% in the first six months of this year, which was led by double-digit growth in all divisions and triple-digit sales growth in the Women's Sport and Sport Active lines.

The company's $587.1 million in second-quarter revenue was an all-time high, and on the company's conference call, its CEO was quite bullish that good days will continue, as new styles have caused demand to explode higher.

While the company was very vague in discussing its backlog moving forward, analysts probed into the issue during the conference call and narrowed its current growth rate to the mid-to-high 20% range. Not to mention, the company's sales to distributors soared 87.3% as it saw a resurgence in Europe and continued demand in Mexico, China, and Australia. In other words, the 37% revenue growth investors saw in the second quarter might not be a fundamental fluke.

A wide disconnect that leads to one conclusion
With all things considered, one of the main reasons that Skechers has soared nearly 200% since 2013 is because the market has essentially had to revalue it as a company with double-digit growth from one with flat growth. This growth, of course, is a result of new product designs and more efficient marketing, which have had an effect that no one on Wall Street could have successfully predicted outside of having a hunch.

Nonetheless, Skechers' second-quarter growth rate actually exceeded Under Armour's 34.2% increase in sales. While Under Armour is a large sports-apparel company, nearly 20% of its revenue comes from footwear, a segment that grew by 34%.

Granted, Under Armour's six-month growth rate of 35% is still superior, but the point is that Skechers is quickly closing the gap that separates the two companies. Yet following Under Armour's solid quarter, its stock soared double-digits, leaving it to trade at nearly 60 times next year's earnings.

Despite Skechers' large stock gains, it's still trading at just 19 times forward earnings, a multiple it shares with lagging footwear designer Crocs. Yet Crocs grew revenue by just 3.6% in its second quarter.

While Skechers is expanding aggressively with both retail stores and manufacturing facilities, Crocs announced plans to close 75 to 100 stores and lay off 3.5% of its workforce following its second-quarter earnings report. Therefore, Skechers is valued like a company with 3% growth that is downsizing. Meanwhile, Skechers has growth that's similar to a company like Under Armour that trades at 60 times forward earnings.

Clearly, this valuation disconnect brings us to one conclusion -- that there is an enormous valuation gap, which implies further long-term upside in shares of Skechers.

Foolish thoughts
Despite Wall Street's best efforts, Skechers' valuation is still not an appropriate reflection of its fundamental improvements. Thus, either Crocs or Under Armour is vastly overvalued or Skechers is foolishly cheap given the fundamental and valuation gap that exists.

In retrospect, the reality might be a little of both. But regardless, Crocs and Under Armour are on opposite ends of the fundamental spectrum, while Skechers operates toward the high side. This fact should leave investors with the clear conclusion that despite trading at new all-time highs, Skechers is still presenting an enormous amount of investment value.

Brian Nichols owns shares of Under Armour. The Motley Fool recommends Under Armour. The Motley Fool owns shares of Crocs and Under Armour. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.