UPDATE: Ms. Jung on Wednesday rejected her agency's statement that she quit voluntarily, saying she was forced out. In a statement released to local media, she said she secured the company's agreement before launching her fashion business in early August. But a month later the agency and the group's other members demanded that she choose either her music career or her venture, a decision she declined to make, she added. Ms. Jung said the agency on Sept. 16 agreed to letting her continue the business activity but was told on Sept. 29 that she was no longer a Girls' Generation member.

Girls'...