article: After the US sportswear company took action, Swiss watch maker Tag Heuer was quick to end its association with the five times Grand Slam winner, and German luxury car marque Porsche said it was postponing any planned activities with her. Sharapova revealed on Monday that she had tested positive for the banned substance meldonium at the Australian Open in January, and faces a ban from tennis of up to four years. Big-name global companies have been attracted to the Russian star for her mix of athleticism and glamour since she won Wimbledon in 2004 at the age of 17. According to US business magazine Forbes, the 28-year-old is now the world's top-earning female sports star, raking in a total of $29.7m last year. Tellingly, the vast majority of that money - some $23m - came from endorsements. And it is the biggest of those endorsements - her eight-year, $70m deal with Nike, which runs until 2018 - that is now under threat. Sharapova is the latest Nike athlete to become embroiled in controversy, with a number of big names before her being dropped, while others have been retained but had the value of their deals slashed. These dropped include cyclist Lance Armstrong, convicted athlete Oscar Pistorius, and boxer Manny Pacquiao, while those in the latter category reportedly include Tiger Woods. Karen Earl, chairman of the European Sponsorship Association, says: "I can't help feeling that Nike has been burnt before; they have stayed with people like Lance Armstrong in the past, and maybe they are just being rightly cautious now. "The use of a suspension is interesting - basically they are saying they will sit and see how things go. Given their recent experiences that is probably a sensible move. I think they have done the right thing this time round. Nike can now have the option of jumping either way," she tells the BBC. Meanwhile, Tag Heuer has been more blunt and "decided not to renew the contract with Ms Sharapova", while Porsche has been more cautious, preferring to put its activities on hold. Now all eyes will be on her other commercial partners - Avon Cosmetics, Evian, Head and skincare brand Supergoop, to see what they do, or whether she is now a tarnished brand for sponsors. Sharapova also has her own confectionery business, Sugarpova, launched in 2011, with sales last year of more than three million bags of sweets. "These other sponsors will be thinking about what they should do now," says Mrs Earl. "In the short-term her continued appeal to sponsors will depend on what action is taken by the tennis and doping authorities. "In the longer term if all seems to be forgiven, and she is not out of the game for longer than the one year that is being talked about, then it might not matter to them as much. Mrs Earl adds: "But if she is not seen to be forgiven by tennis, then sponsors will find her less appealing. It all depends what happens in the next few weeks." The International Tennis Federation (ITF) has
summary: As Nike suspends its relationship with tennis superstar Maria Sharapova not only is one of the most lucrative sports partnerships under threat, but so too could be her phenomenal brand appeal to sponsors.