Guess? Inc. shares fell as much as 16 percent to $15.37 on Thursday after model and actress Kate Upton accused the company's Paul Marciano of sexual harassment.
Upton tweeted on Wednesday its "disappointing that such an iconic women's brand @GUESS is still empowering Paul Marciano as their creative director".
"He shouldn't be allowed to use his power in the industry to sexually and emotionally harass women."
Upton, who was the face of Guess from 2010 to 2011, used the #MeToo hashtag, which has become a rallying cry for the movement against sexual assault and workplace misconduct.
Marciano responded to Upton's allegations through celebrity news website TMZ, saying he never touched Upton, and has never been alone with her. He said he would not apologize as he had done nothing wrong, TMZ reported.
Upton also spoke to TMZ as she walked through Los Angeles International Airport on Wednesday night.
"I'm excited to tell my whole story, but a walk to the car isn't gonna cover it," the Sports Illustrated cover girl said. "I think obviously it's a huge problem."
After the Harvey Weinstein scandal last year, several of Hollywood's biggest names have been accused of sexual harassment and assault in the last few months. The ever-growing list of allegations include actor Kevin Spacey, director Brett Ratner, Oscar winner Dustin Hoffman, NBC host Matt Lauer, hip-hop mogul Russell Simmons, TV journalist Charlie Rose, comedian Louis C.K. and former "Gossip Girl" star Ed Westwick.