Geldmacher serves as Operating Partner at Impact Venture Capital (US) and is an active advisor to various US based IT and telecommunications companies. Prior to his actual engagements he was head of the operating partner team at SoftBank Group International, and president of Sprint Business. He has also served as CEO at Vodafone Global Enterprise, chief commercial officer of the Enterprise Business Unit at Vodafone in Germany, both affiliates of Vodafone Group plc. Prior to Vodafone, Geldmacher served as CEO of British Telecom BT (Germany), a unit of BT Group Plc. Geldmacher has also served as head of international networks and joint ventures at Deutsche Telekom AG in Bonn before also taking on his role as a member of the executive board of T-Systems International GmbH (Germany).