Shares in Bayer took a nosedive on Monday—just days after newly-acquired Monsanto was ordered to pay $289 million in damages to a man who alleged that the company's glyphosate-based herbicides, including the widely used weedkiller Roundup, caused his cancer.

At one point the German pharmaceutical giant's shares fell by as much as 14 percent, Reuters reported, marking a loss in value of roughly $14 billion.

It capped off the U.S. trading day as one of the "biggest losers," ending at a 10-percent loss.

Friday was also a losing day for Monsanto, which Bayer AG controversially acquired for $62.5 billion in June. In a landmark trial, a San Francisco jury unanimously found that the company failed to warn school groundskeeper Dewayne Johnson, who's suffering from non-Hodgkin's lymphoma, and other consumers of the cancer risks from its weed killers, and said the company acted "with malice or oppression."

With this verdict and more than 4,000 other plaintiffs waiting in the wings, @MonsantoCo could be in court for decades to come and it could cost them and its new owner, @Bayer, hundreds of millions – if not billions – of dollars in damages. #Rounduptrial https://t.co/3ZyGr0eWko — carey gillam (@careygillam) August 13, 2018

The International Agency for Research on Cancer (IARC)—a branch of the World Health Organization (WHO)—classified glyphosate as a probable human carcinogen, but Monsanto says its Roundup is safe, and that it plans on appealing.

Monday also marked the last day of the public comment period for the finalization of the merger process, prompting a broad range of advocacy groups to voice their opposition once again.

"No matter how you cut it," said said Daniel Raichel, an attorney with the Nature Program at NRDC, "a Bayer/Monsanto merger spells higher costs for farmers and locks in the chemical-heavy agricultural practices that threaten our health and the bees and other pollinators critical to food security."

"The Department needs to reverse course and block the merger before we all suffer the consequences," he said.