Nike signed Serena Williams to a reported $40 million endorsement deal in 2003.
The agreement was announced in December 2003, after Williams had become one of tennis's biggest stars. Reports described a five-year Nike contract worth nearly $40 million, with performance incentives and a possible three-year extension that could raise the total value substantially.
The deal marked a major change from Williams's previous apparel relationship with Puma, which had sponsored her from 1998 through 2003. Nike's agreement was widely portrayed as one of the richest endorsement contracts ever offered to a female athlete at the time.
The number is sometimes confused with Venus Williams's earlier Reebok deal, also reported at about $40 million over five years. Serena's 2003 sponsor was Nike; the final value of her contract depended on extensions and incentives, so reports differed on the maximum figure.