Monday was a down day for Wall Street, as major market benchmarks gave up ground to start the week. Yet even though many investors pointed to uncertainty about the Trump administration's ability to follow through on some of the promises that it has made to the business community, the stock market nevertheless finished the day with far smaller declines than it had suffered at its worst levels of the day. Again, the propensity for the overall market to rebound from big losses has been impressive, but some stocks still fell sharply. Snap (NYSE:SNAP), Revlon (NYSE:REV), and Ionis Pharmaceuticals (NASDAQ:IONS) were among the worst performers on the day. Below, we'll look more closely at these stocks to tell you why they did so poorly.  

Snap cools off

Shares of Snap finished the day down 12% as the parent company of Snapchat gave back nearly all of its Friday gains following its initial public offering (IPO) last Thursday. The share price closed below the $24-per-share level at which Snap's stock first became available on the open market, and many IPO investors see that level as critical for the success of the offering and of the IPO market more broadly. Wall Street analysts have been highly skeptical of the offering, with sell ratings coming from five different analysts. Post-IPO volatility is nothing new for social media companies, and short-term swoons have sometimes given way to huge gains.

Snap branded glasses with built-in camera.

Image source: Snapchat.

Revlon keeps falling

Revlon stock declined 6%, adding to its losses from Friday following the release of the company's fourth-quarter and full-year 2016 financial report. The cosmetics maker reported a slight decrease in pro forma revenue for 2016 compared to full-year 2015 figures, with a drop of 4% in both sales and profit for the company in the fourth quarter. Revlon has had to work hard to integrate Elizabeth Arden after the two companies' merger in the middle of last year, and CEO Fabian Garcia says that he is "enthusiastic about the opportunities presented by our newly combined company's enhanced portfolio of brands, size, scale, profitability, and international growth momentum." Yet despite anticipated savings from cost synergies and economies of scale, Revlon nevertheless has some long-term investors worried about whether its restructuring will pay off as much as the company hopes.

Ionis drops despite solid trial results

Finally, shares of Ionis Pharmaceuticals fell 8%. The RNA-targeted drug development specialist said that its phase 3 trial of triglyceride-fighting drug volanesorsen met its primary endpoint of reducing triglyceride levels in patients with familial chylomicronemia syndrome, a rare genetic disorder characterized by high triglyceride levels and risks of severe pancreatitis. Mean reduction of triglyceride levels was 77% from baseline after three months of treatment, compared to an increase for those with placebo, and half of those who entered the study with more than 750 milligrams of triglycerides per deciliter of blood saw those levels fall below 500 within three months. Those connected with the study argued that the results suggest a favorable risk-benefit profile for the drug, but there were some side effects that caused some consternation among investors who looked more closely at the results. It remains to be seen whether the FDA will have the same problem with declines in platelet counts and other concerns when it decides whether to approve volanesorsen in the future.

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