The stock market dealt with some ups and downs on Thursday, with most major benchmarks finishing about a half a percent higher. Investors tried to balance encouraging news on the trade and monetary policy fronts against the continuing risks of deterioration in the economic prospects for both the U.S. and the world more broadly. Some companies had to deal with bad news that sent their shares sharply lower, and American Airlines Group (AAL 1.42%), Barnes & Noble (BKS), and WD-40 (WDFC 1.28%) were among the worst performers. Here's why they did so poorly.

American Airlines loses altitude

Shares of American Airlines Group fell 4% after the airline giant warned that its fourth-quarter results wouldn't be as good as some had hoped. American specifically said that its key revenue per available seat mile metric grew just 1.5% during the quarter, which was at the lower end of the guidance range it had provided, and full-year adjusted earnings projections came in below what most of those following the stock had anticipated. Economic uncertainty has weighed on airline stocks lately, but if the economy can avoid a recession, then low fuel prices should help bolster American's profits during 2019.

Check out the latest American Airlines earnings call transcript.

American Airlines airplane on a taxiway, with airport buildings in the distance.

Image source: American Airlines.

Is the book closing on Barnes & Noble?

Barnes & Noble stock lost 16% in the wake of downbeat guidance provided in the company's holiday sales results. The bookseller said that comparable-store sales were higher by 4% between Black Friday and New Year's Day, with a 1.3% rise in the nine-week period ending Dec. 29. Yet to get that sales increase, Barnes & Noble boosted its spending on advertising and promotional activity, and the company projects that those costs could result in as much as a 10% cut to its previous earnings guidance. For the long-ailing company, that's just more bad news that threatens Barnes & Noble's long-term viability as a brick-and-mortar retailer.

Check out the latest Barnes & Noble earnings call transcript.

WD-40 slides despite solid results

Finally, shares of WD-40 dropped 7%. The company famous for its WD-40 solvent reported fiscal first-quarter results that included a 4% rise in sales and a 5% jump in net income. CEO Garry Ridge was generally pleased with the company's performance, noting that its Specialist product line saw double-digit percentage increases in revenue from year-ago levels. Yet investors seemed to focus on sales declines of 10% in the Asia-Pacific segment, and although Ridge said such temporary drops are "quite normal," some worry that the pause in a region that for many companies has been a key driver of global growth could point toward further challenges ahead.

Check out the latest WD-40 earnings call transcript.