On social media and elsewhere, the reaction has been swift: TV host Megyn Kelly and actresses Mia Farrow and Rose McGowen have said they will stop buying Donna Karan products, and an online petition with more than 8,000 signatures is calling on Nordstrom to drop DKNY and other Donna Karan-branded apparel, bedding and accessories. (Beginning in February, Macy’s will be the exclusive retailer of DKNY products.)

Shares of the company that owns Donna Karan International have fallen nearly 10 percent since last week. Stocks closed down more than 2 percent on Thursday to $26.03 a share.

“What she did was a terrible mistake,” Paula Rosenblum, managing partner of Retail Systems Research, wrote in an email. “General consensus is she just broke her brand.”