This post may contain affiliate links. Please read our disclosure policy.
The Williams Sisters
image via?SI VaultAge: Venus (15), Serena (16)
Brand: Venus (Reebok), Serena (Puma)
At the age of 15, Venus Williams signed a $12 million dollar deal with Reebok, followed by a $40 million dollar contract with the brand four years later. Her younger sister Serena signed with Puma at 16 for a five-year deal that was eventually worth $13 million.