Wall Street suffered through a tough session on Friday, with the Dow Jones Industrial Average finishing lower by almost 600 points and other major benchmarks enduring declines of 2% to 2.5%. Market participants attributed most of their nervousness to the Trump administration's decision to fire another salvo in the emerging trade war between the U.S. and China, announcing plans to add further tariffs totaling an extra $100 billion against the Asian economic power. Hawkish comments from Federal Reserve Chair Jay Powell also added to the tension among investors, and many stocks got hit especially hard by the geopolitical rhetoric and other news. Square (SQ -0.42%), U.S. Steel (X -0.06%), and Conn's (CONN -2.23%) were among the worst performers on the day. Here's why they did so poorly.

Square deals with e-commerce fallout

Shares of Square fell 4.5% after reports surfaced that the payment processing specialist might become the latest victim of the burgeoning e-commerce industry. According to reports from The Wall Street Journal, Amazon.com (AMZN -0.17%) is looking closely at creating its own system for making peer-to-peer payments, utilizing its Alexa voice-controlled digital assistant as a potential platform. Square and some of its rivals in the payment space have benefited greatly from the rise of e-commerce, but Amazon's move could once again change the playing field by bringing another behemoth corporation into the space. Square still has plenty of room to grow, but if Amazon can eliminate part of its addressable market, it would be a blow for the company.

Square logo with concentric squares in black and white and the company name.

Image source: Square.

U.S. Steel gets ready for (trade) war

U.S. Steel stock dropped 6% in the latest in a series of volatile moves in both directions during recent trading sessions. Investors have been hard-pressed to figure out exactly how the quick-paced volleys in the trade dispute between the U.S. and China will eventually affect its business, initially sending the stock dramatically higher in anticipation of tariffs but then simmering down. Recent indications that Chinese steel prices might fall in the near future could prevent U.S. Steel from getting as much benefit from a 25% steel tariff as it would otherwise get if steel prices in China remained stable. Even with tariffs, U.S. Steel has work to do to maximize its own profit potential.

Conn's keeps falling

Finally, shares of Conn's lost 10%. The stock had already fallen by a double-digit percentage on Thursday following a fourth-quarter financial report that included declining revenue and a large 8% drop in same-store sales. Today's drop followed through on downbeat sentiment about the furniture and appliance retailer, perhaps in part due to the potential impact that escalating trade tensions could have on the retail industry. After suffering through years of difficult industry conditions, Conn's can only hope that it will be able to turn things around in the coming year and overcome some of the lingering challenges that have held back its growth recently.