E.ON SE (marketed with an interpunct as E·ON) is a European holding company based in Essen, North Rhine-Westphalia, Germany. It runs one of the world's largest investor-owned electric utility service providers. The name comes from the Greek word aeon which means an age. The company is a component of the Euro Stoxx 50 stock market index. It operates in over 30 countries and serves over 33 million customers. It is one of the 30 members of the DAX stock index of major German companies and a member of the Global Titans 50 index.