Cristiano Ronaldo is facing sponsorship withdrawal worth $US 1 billion amidst the reopening of a rape allegation investigation.

Las Vegas police have reopened the investigation into the 2009 case that saw Ronaldo settle with a $375,000 payout and a non-disclosure agreement for the alleged victim.

Sponsor, Nike, who had a contract with the Italian soccer player since 2003, and EA Sports, have both issued statements expressing deep concern with the allegations.