Friday was a poor end to the week on Wall Street, as the Dow Jones Industrial Average lost almost 200 points and other major benchmarks saw similar losses on a percentage basis. A swift turn in relations between the U.S. and NATO partner Turkey was the most popular scapegoat for the decline in market participants' eyes. Tweets from the U.S. president threatened to double tariffs on steel and aluminum from their already steep levels, marking the latest in a diplomatic row that has shown no signs of easing. Adding to the pressure on stocks was bad news from several individual companies. News Corp. (NASDAQ:NWS) (NASDAQ:NWSA), Diebold Nixdorf (NYSE:DBD), and Dropbox (NASDAQ:DBX) were among the worst performers on the day. Here's why they did so poorly.

News Corp. disappoints

News Corp. shares dropped about 13% after the news and media giant reported its fiscal fourth-quarter financial results. Despite nearly 30% revenue growth, earnings at News Corp. slid from year-earlier levels. Some areas within News Corp. were surprisingly strong, with the book publishing unit posting record revenue and digital revenue seeing the positive impact of high digital subscriber growth rates. However, much of News Corp.'s business remains under pressure, and the media giant will have to make further strategic shifts in order to execute a full turnaround and find the best path forward to rediscover growth.

News Corp. logo.

Image source: News Corp.

Diebold keeps diving

Diebold Nixdorf stock fell another 17%, bringing its losses over the past three days to more than 35%. The automated teller machine specialist had to reduce its guidance for the full 2018 year after reporting a surprise loss for the second quarter, as costs ballooned for the company. Problems have gotten bad enough that Diebold has chosen to take steps to negotiate with its creditors in an attempt to modify its credit agreement. With interest rates on the rise, now isn't the time to have trouble with your primary source of capital, and until Diebold can get its ATM business turned around and find other avenues for future growth, investors will be nervous about what's coming next for the company.

Investors drop Dropbox

Finally, shares of Dropbox finished lower by 10%. The cloud storage specialist reported what seemed to be extremely good second-quarter results, including gains in sales, paid user counts, revenue per user, and a doubling in adjusted net income. Yet some shareholders reacted negatively to the departure of the company's chief operating officer, and others are nervous about the rising level of competition in the cloud storage space. Dropbox still has a valuable first-mover advantage against its rivals, but investors nevertheless haven't seen any sustainable upward move since the company came public in March.

Dan Caplinger has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.