The stock market had a mildly positive day on Friday, and gains of between 0.1% and 0.3% were common for most of the major benchmark indexes. Without any outright hostility among leaders of the G-7 nations in their summit in Canada's Quebec City, investors seemed content to go into the weekend with confidence in the prospects for the U.S. economy and its biggest businesses. Yet some individual companies had bad news that held their shares back from participating in the rally. Nabors Industries (NBR -0.69%), PolarityTE (PTE), and Evolus (EOLS 1.65%) were among the worst performers on the day. Here's why they did so poorly.

Nabors sells more stock

Shares of Nabors Industries fell 4.5% as the operator of land-based and offshore rigs in the U.S. and abroad made an announcement about a recent stock offering. Last month, Nabors agreed to sell 35 million shares at $7.75 per share, raising roughly $271 million. At the time, though, the underwriters retained the right to purchase another 5.25 million shares if they so chose. Nabors said that its underwriters had exercised that right in full, paying $39.4 million. Given that shares had started the day below the $7.75 level and ended well under it, it's likely that underwriters had entered hedging transactions to protect themselves from downward moves shortly after the initial offering. Unwinding those hedges and the prospect of further dilution from additional share issuance likely combined with a drop in oil prices and uncertain future for the company to push Nabors stock lower.

Eight workers wearing hardhats in front of a drilling rig on sandy ground under a clear blue sky.

Image source: Nabors Industries.

Citron strikes again

PolarityTE stock dropped 3% after short-seller Andrew Left at Citron Research tweeted negative comments about the company. In the tweet, Citron compared the regenerative tissue-focused biotech stock to MiMedx Group, which recently said that it would have to restate financial results going back several years. Setting a price target of $16 per share, Citron asserted, "No reason to commit fraud like [MiMedx] when you can just promote your stock with NOTHING like [PolarityTE]." Even with the decline, PolarityTE stock is still up by more than 65% since the beginning of May following a drop related to a stock offering.

Evolus gives back some ground

Finally, shares of Evolus lost 17.5%. The aesthetic procedures and treatments specialist's stock had been on a huge run, jumping fivefold between early May and Wednesday's close on building excitement about the company's possible rival treatment to Botox. Evolus has seen considerable turbulence along the way, with a brief drop coming after the U.S. Food and Drug Administration issued a complete response letter rejecting its DWP-450 candidate treatment. Yet the FDA didn't require any additional studies, and investors seemed to take that as a green light to keep bidding the stock higher. Today's drop wasn't motivated by any obvious news and looks more like a brief bout of profit-taking after an outsize run-up for the stock.