If I'm not mistaken, Henin, Venus and Serena are all at $17 million.
After Us Open they'll all be around 18 mil... I believe Serena/ Venus will be slightly above and henin slightly Below... Im fairly certain the sisters have bigger endorsements though Whats interesting is Venus and Henin's win lose records are almost identical...
Henin: 43-4 457-103
Serena:26-5 346-72 (play some more....)