Seven WTA players made the recently unveiled Bloomberg "Sportfolio"/Horrow Sports Ventures 2013 Power 100.
A record 15 women made the list, led by Serena Williams at No.12. Other WTA players on the list were Maria Sharapova at No.20, Victoria Azarenka at No.32, Venus Williams at No.57, Petra Kvitova at No.79, Caroline Wozniacki at No.80 and Agnieszka Radwanska at No.89.
Williams has lucrative endorsement deals with Gatorade, Wilson and Nike and has a clothing line that sells on Home Shopping Network. Serena and sister Venus, who also has her own clothing line, starred in an Apple iPhone ad earlier this year and both have significant social media presences.
Sharapova earns about $6 million in on-court prize money annually, and her endorsement and appearance deals are worth a reported $22 million annually, making her the world's highest-paid female athlete.
NBA star LeBron James came in at No.1 on the list. The highest-rated tennis player was Roger Federer at No.5.
The most powerful athletes on and off the field were determined by Rick Horrow, host of Bloomberg TV "Sportfolio" and CEO of Horrow Sports Ventures; CSE, a leading integrated marketing agency; the Nielsen/E-Poll N-Score; and BSports. The rankings are based 50% on these "off-field" measurements, and 50% on "on-field" performance using a variety of industry statistics.
"This is the fourth year of the Power 100, and it continues to command attention as an invaluable tool to evaluate an athlete's brand and measure his or her market value," Horrow said. "In today's 24/7 news cycle, as athletes increasingly dominate front page headlines well out of the sports section, their endorsement contracts are increasingly under scrutiny."