Nov 24 (Reuters) - Adidas AG (ADSGn.DE) on Thursday said it has launched an investigation into allegations of inappropriate behavior by Kanye West, after the German sporting goods maker last month ended its partnership with the rapper and fashion designer.Adidas said it initiated the probe after receiving an anonymous letter making several allegations against the musician, who now goes by Ye.According to the magazine, former members of the team sent an anonymous letter to Adidas in which they said senior leaders at the company were aware of Ye's behavior, but had turned a "blind eye" and "turned their moral compass off."Union Investment, which owns a 0.76% stake in Adidas, wrote to the company asking for more information about the claims."Adidas needs to disclose when the management and the supervisory board was first informed about the internal allegations," Janne Werning, who heads ESG Capital Markets & Stewardship at Union Investment, said in a statement to Reuters."