Stefan, Executive Chairman and first investor of Last.fm until it got sold to CBS in 2007 for USD 280m, is one of the most active business angels in Europe’s digital space. Currently he acts as Executive Chairman at the research community Mendeley.com and at RjDj.me. Stefan is a serial entrepreneur since he left university: in 1998 he founded ricardo.de, Germany’s biggest online-auction company, which he took to an IPO at Neuer Markt in 1999. The company merged to QXLricardo in 2000 before got sold to Nasper in 2007, for USD 1.8 billion. Stefan is currently invested in 25 plus companies and enjoys living in London. He holds a PhD in foreign exchange risk management and was a professional DJ for 15 years.