Guess Inc (GES.N) said on Tuesday its co-founder Paul Marciano will give up his day-to-day responsibilities at the company on an unpaid basis pending the completion of a probe into accusations of improper conduct.

Earlier this month, model and actress Kate Upton accused Marciano of using his power in the fashion industry to harass women. Marciano and the company have both denied the claims.

"The company takes very seriously any allegations of sexual misconduct, is committed to maintaining a safe work environment, and looks forward to the completion of a thorough investigation of all the facts," it said in a statement.

Guess' shares fell more than 17 per cent in early February following Upton's accusations against Marciano made on Twitter.

“He shouldn’t be allowed to use his power in the industry to sexually and emotionally harass women #metoo”, Upton tweeted, using a popular hashtag designed to highlight the wide spread of sexual harassment, without elaborating.

Shortly after, the company's board formed a special committee made up of two independent directors to oversee an investigation into accusations against Marciano.

The investigation is being conducted by law firm O'Melveny & Myers while the special committee hired law firm Glaser Weil to look into the accusations.

Guess shares were down about 4 per cent at $14.93 in early trading on Tuesday.