The stock market plunged on Tuesday, as investors responded to worries that a trade agreement between the U.S. and China might not come as quickly as some had hoped following the two countries' announcements after the G-20 summit in Argentina. Major indexes were down 3% to 4%, and winning stocks were hard to come by. There was more than enough red ink to go around among individual shares, but some companies were noteworthy for the causes and extent of their declines. Intel (NASDAQ:INTC), Barnes & Noble Education (NYSE:BNED), and Veeva Systems (NYSE:VEEV) were among the worst performers on the day. Here's why they did so poorly.

Intel faces competition

Intel shares closed lower by 5%, putting it among the worst-performing stocks in the Dow Jones Industrial Average. Stock analysts at Northland Capital panned the semiconductor giant, cutting their rating on Intel from market perform to underperform and reducing their price target on the stock by $4 to $42 per share. Analysts believe that Intel's size and structure make it difficult for the company to react quickly to changing market conditions, giving chip rival Advanced Micro Devices a competitive advantage. With many challenges to face, Intel will continue to have to work hard in order to hold its own in a fast-evolving tech sector.

Room with curved wall with Intel logo on it, along with neon-blue baseboards and six chairs in the room.

Image source: Intel.

Will Barnes & Noble Education learn its lesson?

Shares of Barnes & Noble Education plunged nearly 31% after the company released its fiscal second-quarter financial report. The operator of college bookstores said that revenue was down 8% compared to the prior-year period, although adjusted earnings rose by 20%. Lower comparable-store sales were particularly troubling to those watching the stock, and despite CEO Michael Huseby's assurances that the company is "taking steps to improve our sales execution and more aggressively manage expense and capital spending during this transformation to digital platforms and offerings for the future," investors seem skeptical that the beaten-down retailer can keep straddling the fence between e-commerce and a brick-and-mortar model.

Critics hit Veeva

Finally, Veeva Systems stock lost 6%. The software-as-a-service specialist for the healthcare industry found itself the latest target of short-selling research specialist Citron Research, which said that Veeva shares have moved too high, too quickly and that an overall market correction would hit the company's stock especially hard. Veeva has thus far avoided much of the decline that has sent many high-flying technology stocks sharply lower recently, but Citron's convinced that new competition could be the catalyst to send shares lower. The short recommendation puts Citron in direct conflict with Veeva's recent results, which have suggested solid performance and plenty of growth potential ahead.

Dan Caplinger has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Veeva Systems. The Motley Fool has a disclosure policy.