Wall Street celebrated a solid start to earnings season on Wednesday, sending the Dow Jones Industrial Average to triple-digit gains and producing more modest increases for other popular stock indexes. Even though the market correction near the end of 2018 raised concerns about a potential economic slowdown, few of the financial results that investors have seen thus far have supported that proposition. Yet not all of the day's news was positive, and some companies saw their stocks punished as a result. Ford Motor (NYSE:F), Snap (NYSE:SNAP), and Aptinyx (NASDAQ:APTX) were among the worst performers. Here's why they did so poorly.

Ford hits the brakes

Shares of Ford Motor were down 6% after the automaker reported preliminary results for the fourth quarter. The company said that earnings per share were down by more than half from year-earlier levels, and even after adjusting for extraordinary items, its bottom line was weaker than most had expected. A host of factors, including a strong dollar, weak business conditions in China, and higher-than-expected warranty costs in its home North American market hurt Ford. Moreover, Ford's reluctance to offer specific guidance for 2019 made shareholders even more nervous. Investors will have to wait for the full report next week for further details.

Blue Ford Mustang on a left-curving road, with brake lights on.

Image source: Ford Motor.

Snap loses its CFO

Snap saw its stock drop 14% in the wake of its chief financial officer's decision to leave the company. CFO Tim Stone just joined Snap last spring, and many investors thought that his experience in e-commerce could help the social media company be more shareholder-friendly. Indeed, Snap did start offering financial guidance under Stone's tenure, but the Snapchat operator's fundamental business performance has been weak, including falling user metrics and rising costs. For many, the news seems to be just one more bad mark against Snap and its controversial CEO.

Aptinyx suffers a clinical trial setback

Finally, Aptinyx shares plunged, falling more than 66%. The biopharmaceutical company announced that its candidate treatment for diabetic peripheral neuropathy, NYX-2925, failed to meet the primary endpoint in its phase 2 clinical trial, as it couldn't demonstrate a statistically significant advantage over a placebo when measuring change in average daily pain scores during the final week of treatment compared to baseline levels. Aptinyx tried to cushion the blow by noting that there were what it called "meaningful improvements on pain and other endpoints" within the study, but investors remain troubled that the biopharma's most advanced clinical trial failed to deliver better results.

Dan Caplinger owns shares of Ford. The Motley Fool recommends Ford. The Motley Fool has a disclosure policy.