Maria Sharapova could lose millions in future sponsorship earnings, after partners such as Nike, Tag Heuer and Porsche moved responded with concern to her admission of failing a drugs test.
Sportswear giant Nike said it was "saddened and surprised" by Sharapova's confession that she had tested positive for meldonium, a substance added to the World Anti-Doping Agency's (Wada) banned list on 1 January 2016, and moved to suspend its relationship with the Russian tennis star.
Sharapova earned around £16m from endorsements last year and was named the highest-earning female athlete in the world by Forbes.
Yet the five-time grand slam champion could miss out on over £20m if Nike - with whom she has enjoyed a relationship since she was 11-years-old - chooses to drop her from its roster permanently as there are still three years remaining on an eight-year contract worth £43m.
Porsche said they would "postpone planned activities" with the 28-year-old while Swiss watchmaker Tag Heuer has "suspended negotiations" to renew an endorsement deal that expired at the end of last year.
Mineral water manufacturer Evian said: "Until now, we have maintained a trustworthy professional relationship.
"Evian attaches great importance to health, to integrity and to transparency, and we will follow closely the development of the investigation."