“We are deeply concerned by the disturbing allegations and will continue to closely monitor the situation,” a Nike spokesman said to AFP.
Portugal and Juventus star Ronaldo, who has denied the allegations against him dating from an incident in 2009, signed a lifetime endorsement deal with Nike in 2016.
According to Forbes magazine, Ronaldo is one of only three athletes to have been given a lifetime deal with Nike, joining an elite club whose other members are NBA icons LeBron James and Michael Jordan.
Police in Las Vegas announced this week they were reopening a rape case after allegations made by a former model, Kathryn Mayorga, went public.
Mayorga, 34, has accused Ronaldo of raping her in a Las Vegas hotel suite on June 13, 2009.
On Wednesday the former Manchester United and Real Madrid star denied the allegation, describing rape as “an abominable crime that goes against everything that I am and believe in.”
“Keen as I may be to clear my name I refuse to feed the media spectacle created by people seeking to promote themselves at my expense,” Ronaldo said on Twitter.
“My clear conscious (sic) will thereby allow me to await with tranquillity the results of any and all investigations,” he added. DM
"The end may justify the means as long as there is something that justifies the end." ~ Leon Trotsky