Who invests in your company really matters.
Just ask Weight Watchers, whose shares were up more than 15% in midday trading on Thursday after talk show superstar Oprah Winfrey said she'd lost more than 40 pounds using the company's weight loss regimen.
“I'm eating everything I love — tacos, pasta. I've never felt deprived,” Oprah said in a new ad, out Thursday, that shills for Weight Watchers.