Oprah steps down from Weight Watchers board, stock plunges 25%
• Oprah Winfrey stepping down from Weight Watchers board after nearly 9 years • Announcement sent Weight Watchers stock plunging 25% in early trading • Comes months after Winfrey revealed she was taking medication for weight loss • Winfrey has been most prominent spokeswoman for Weight Watchers since 2015 • Her endorsement convinced many people to sign up, analysts said