Mary-Kate & Ashley Olsen
The Olsen twins' popularity began when Mary-Kate and Ashley were just 9 months old, appearing as baby Michelle on the television show Full House. At just 7 years old, the mini-moguls co-founded Dualstar to market their images to tweens around the world—from DVDs to cosmetics to furniture. At 18, the girls took over the company, estimated to be worth millions.
Photo: George Burns/Harpo Studios