United Internet AG is a German

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 Internet services company. With 2.91 million DSL customer contracts, it is a leading ISP

Internet service provider

An Internet service provider is a company that provides access to the Internet. Access ISPs directly connect customers to the Internet using copper wires, wireless or fiber-optic connections. Hosting ISPs lease server space for smaller businesses and host other people servers...

 in Germany. It is headquartered in Montabaur

Montabaur

Montabaur is a town and the district seat of the Westerwaldkreis in Rhineland-Palatinate, Germany. At the same time, it is also the administrative centre of the Verbandsgemeinde of Montabaur – a kind of collective municipality – to which 24 other communities belong...

, Rhineland-Palatinate

Rhineland-Palatinate

Rhineland-Palatinate is one of the 16 states of the Federal Republic of Germany. It has an area of and about four million inhabitants. The capital is Mainz. English speakers also commonly refer to the state by its German name, Rheinland-Pfalz ....

. Since 2003 it is listed on the TecDAX

TecDAX

The TecDAX stock index tracks the performance of the 30 largest German companies from the technology sector. In terms of order book turnover and market capitalization the companies rank below those included in the DAX.The TecDax was introduced on 24 March 2003...

.

United Internet operates its own Internet backbone

Internet backbone

The Internet backbone refers to the principal data routes between large, strategically interconnected networks and core routers in the Internet...

 with computer clusters at several Internet exchange point

Internet Exchange Point

An Internet exchange point is a physical infrastructure through which Internet service providers exchange Internet traffic between their networks . IXPs reduce the portion of an ISP's traffic which must be delivered via their upstream transit providers, thereby reducing the average per-bit...

s (DE-CIX

DE-CIX

Deutscher Commercial Internet Exchange is an Internet Exchange Point situated in Frankfurt ....

, INXS

INXS

INXS are an Australian rock band, formed as The Farriss Brothers in 1977 in Sydney, New South Wales. Mainstays are Garry Gary Beers on bass guitar, Andrew Farriss on guitar/keyboards, Jon Farriss on drums, Tim Farriss on lead guitar and Kirk Pengilly on guitar/sax...

, AMS-IX, LINX

Linx

Linx AB was a railway company which operated inter-Scandinavian passenger trains between 2001 and 2004. Established as a joint venture between the Norwegian State Railways and the Swedish state-owned SJ, Linx operated the routes from Oslo, Norway, to Stockholm, Sweden, and from Oslo via...

).

In July 2008 United Internet AG acquired a 30% stake in Jimdo GmbH.

United Internet AG's subsidiary 1&1 Internet AG acquired the DSL business from freenet AG for EUR 123 million in May 2009.