15. Maria Sharapova has won 4 Grand Slam titles and held the No 1 ranking. She has become a major brand in the USA and across the globe. Endorsements & fashion deals with Nike, Evian & Samsung will now be alongside the new Porsche deal she struck in April. Sharapova is highly marketable because she appeals to both females and males. She has also invested long-term with her own candy line, Sugarpova, which stretches her brand out to kids.