The stock market has put in a strong performance so far in 2017, with the S&P 500 (^GSPC 0.25%) recently hitting new all-time record highs. But not every stock in the market has shared the success of the broader indexes. In particular, Under Armour (UAA 2.24%), Transocean (RIG -1.28%), and U.S. Steel (X -1.60%) have all lost at least 30% of their value year to date. Given the challenges they face, some investors are concerned that their losses could become even more severe in the months to come.

UAA Chart

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Under Armour sees growth slow

For years, Under Armour was a growth darling in the athletic apparel and footwear industry, building up its business and taking full advantage of demographic trends favoring greater demand for its products. Yet recently, Under Armour has struggled, reporting only single-digit percentage growth in its most recent quarter and making investors increasingly nervous about the company's ability to sustain a high-growth trajectory going forward.

Retail pressures have hurt Under Armour, because many of the sporting goods store chains that carried its products have gone bankrupt or otherwise closed their stores. Some investors are also concerned about whether Under Armour will invest enough in its e-commerce distribution infrastructure to keep up with competitors. Still, international growth remains robust, and both Europe and Japan have seen solid growth rates that point to the prospects for future success as well. In a competitive environment, Under Armour will have to fight harder, but it has the potential to rebound from its losses.

Under Armour bag.

Image source: Under Armour.

Transocean loses energy

Transocean shares have also been a victim of a tough industry environment, as the oil and gas sector hasn't been able to recover as fully from terrible performance in 2015 as investors had hoped. In particular, Transocean suffers because of its exposure to the offshore drilling industry, where price declines in crude oil have had an especially harsh impact on drilling activity and the need for the company's services. The drilling specialist has worked hard to cut its costs, but there's only so much expense control possible, and utilization rates have plunged on what in the past were some of Transocean's most lucrative assets.

Transocean is now looking at ways that it can bolster its business going forward, and some believe that the offshore drilling specialist will get more aggressive in the near future. In particular, possible moves would include making a major acquisition in an effort to consolidate the market and capture greater pricing power. Transocean is pleased that some projects that used not to be economically viable have seen their breakeven points fall to $40 to $50 per barrel, but what it really needs to see is a sustained push for crude above those levels in order to spur more dramatic demand.

U.S. Steel can't deliver

Finally, U.S. Steel has taken a huge hit so far this year. Enthusiasm built up toward the end of 2016, as the incoming Trump administration emphasized the need for infrastructure projects to bolster the U.S. economy. Many saw that as a cue for U.S. Steel to ramp up production of needed materials to support construction efforts. Since then, however, the White House has run into resistance on its domestic agenda, and that has held the steel industry back.

U.S. Steel's most recent quarterly results reflected the disappointment that investors have had. Sales were up 16% from the previous year's period, but the company saw its overhead expenses nearly double compared to the fourth quarter of 2016, and that produced a surprise loss for U.S. Steel. Because it waited until now to take on tasks like upgrading its production facilities and seeking to eliminate unnecessary expenses, U.S. Steel hasn't been as quick on the uptake as some of its peers. With years of capital improvements anticipated, it's possible that U.S. Steel will take a lot longer to cash in even if things go well for the steel industry generally.

Losses of 30% are always tough for investors to swallow, and it's smart to reexamine your investing thesis when such losses occur to see if you still have confidence in the stock. Rebounds for all three of these stocks are possible, but they will all depend at least in some part on external factors outside their control in order to succeed.