Monday wasn't a great day on Wall Street, but it wasn't all that bad for investors. Most major indexes suffered losses of less than half a percent despite ongoing concerns about whether trade disputes across the globe will get resolved favorably. Some investors are hopeful that a solid earnings season will make it easier for the markets to have greater confidence, but at least for now, many people seem a bit pessimistic about the immediate future. Some stocks took especially hard hits, with Aurora Cannabis (NYSE:ACB), Sorrento Therapeutics (NASDAQ:SRNE), and NGM Biopharmaceuticals (NASDAQ:NGM) finishing among the worst performers. Here's why they did so poorly.

Marijuana's malaise hits Aurora

Shares of Aurora Cannabis fell almost 7%, adding to recent losses and continuing the weak performance of the marijuana sector more broadly. Analysts have been largely negative about the prospects for cannabis stocks, with BMO cutting its 2021 revenue forecast by more than 20% to roughly $425 million. Analysts pointed to a glut of pot products in Canadian provincial markets, and it's likely that prices will come down, hitting profit margin levels for Aurora and its peers. As competition grows fiercer in the marijuana space, Aurora Cannabis will have to work harder in order to differentiate itself and seek ways to promote value-added branding and products.

Marijuana leaf on top of a pile of similar leaves.

Image source: Getty Images.

Sorrento sells shares at an unfortunate time

Sorrento Therapeutics plunged more than 25% after the biopharmaceutical company announced a sale of stock. Sorrento turned to institutional investors to make a direct offering of 10.87 million shares, raising about $25 million. However, along with the shares, investors also obtained warrants to purchase additional stock at $2.40 per share. That feature diluted the interest of existing investors, and they weren't happy with that part of the deal. With Sorrento having seen big disappointments earlier this year, the timing wasn't great to look for more capital.

Trial results send NGM lower

Finally, shares of NGM Biopharmaceuticals lost over 20%. The company announced what it called positive interim results in a phase 2 study of its aldafermin treatment for nonalcoholic steatohepatitis (NASH), including a statistically significant reduction in liver fat content. However, investors seemed to want clearer evidence of aldafermin's advantage over other potential NASH treatments. Analysts at Stifel called the stock's drop unwarranted and recommended buying on weakness. Yet NGM hasn't done well since its early 2019 IPO, and some fear that the company might not emerge victorious on this key front in the medical profession.