2015 the appoval of the first 3U-developed wind farm project is received.
2014 the competences within the area of renewable energies, especially wind energy, are strengthened significantly by the acquisition of 3U ENERGY PE GmbH (a wind farm project development company) and an existing wind farm in Langendorf, Saxony-Anhalt. Due to a changing ownership structure, the name of EuroSun Vacuum-Solar-Systems GmbH changes to 3U Euro Energy Systems GmbH.
2013 the acitivites related to data center services are intensified by the purchase of two additional data centers in Berlin and Hanover in order to support the existing data centers in Marburg and Frankfurt.
2012 saw the startup of ClimaLevel Energiesysteme GmbH to market a high quality underfloor system for heating, cooling, ventilation and wiring. The same year, PELIA Gebäudesysteme GmbH, a production and trading company and provider of purchasing and logistics services, was founded. Also in 2012, the following 3U subsidiaries were renamed: SEGAL Systems GmbH became weclapp GmbH, 3U SOLAR Systemhandel AG became 3U ENERGY AG and 3U SOLAR Service GmbH became Immowerker GmbH. The names were changed to reflect changes in each company's product portfolio.
2011 began successfully with the sale of subsidiary LambdaNet. Shortly thereafter, Selfio GmbH, an online retailer for underfloor heating, ventilation and solar heating systems, chimneys, and fireplaces is established.
2010 a new subsidiary EuroSun Vacuum-Solar-Systems GmbH extends our footprint in the renewable energy sector to produce thermal solar units with a focus on vacuum tube collectors. Also in 2010, the sales and marketing resources of the 3U Group were pooled into 3U Dynamics GmbH
2009 3U HOLDING AG extends its work in the renewable energies sector when it founds 3U SOLAR Systemhandel AG. In addition, the companies 3U MOBILE GmbH and Spider Telecom GmbH strengthen our offerings in telephony and RISIMA Consulting GmbH strengthens our services portfolio.
2008 The carrier identification code 01067 is started in open call-by-call at our subsidiary Linecall Telecom GmbH. In the same year, SEGAL Systems GmbH is founded by spinning off the Group's IT department into an independent company.
2007 The extraordinary general shareholders meeting decides that 3U TELECOM AG should in the future position itself as a management and holding company. On November 1, 2007, the company's name is changed from 3U TELECOM AG to 3U HOLDING AG. The telecommunications services are spun off and become a new wholly-owned subsidiary, 3U TELECOM GmbH.
2006 New open call-by-call subsidiaries are started: 010 017 Telecom GmbH with the carrier identification code 010 017 and Discount Telecom S&V GmbH with the 01017 carrier identification code.
2004 3U TELECOM AG acquires LambdaNet Communications Deutschland AG to unlock significant growth potential in the expanding IP/broadband sector. In addition, a new offer gains additional phone customers: Subsidiary fon4U goes on the market with the dialing code 01053.
3U is upgraded to the “Prime Standard” segment on the stock exchange in January 2003. 3U TELECOM AG continues its growth with the purchase of the brand OneTel, which was a successful voice telephony operator with the carrier code 01086 for residential and business customers in the German market.
In May 2001 , the general meeting decides to change the company name to 3U TELECOM AG. The decisive factor is the progressive expansion of the company abroad, as shown in the company starting operations in Switzerland, Austria, the Netherlands, Italy, France, USA, Belgium, Luxembourg, and the UK between 2000 and 2004.
In September 1999, the company became a publicly traded company (Aktiengesellschaft) and was listed on 11/25/99 on the Neuer Markt of the Frankfurt Stock Exchange.
1997 3U HOLDING AG is founded 3U Telekommunikation GmbH to provide network communications.