Ms. Tolleson, senior corporate VP of sports agency International Management Group, also has helped Ms. Williams craft a marketing plan that creates strong relationships with companies. Among Ms. Williams' other major endorsements are Avon Products and Wm. Wrigley Jr. Co.
"When we've talked to companies, we've said we're looking for relationships where the endorsement side is there, but also some sort of community or educational component," says Ms. Tolleson, 45.
Burns Sports & Celebrities estimates Ms. Williams-who last month defended her U.S. Open title against her sister Serena-is the No. 1 female tennis endorser, with 2001 endorsements worth $12 million to $14 million. Burns President Bob Williams says Ms. Williams is followed by No. 2 female endorser Anna Kournikova, whose 2001 endorsement deals are estimated at under $9 million.