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Buy&Build investments -  Strategic partners with outstanding skills in digital
Tilman Au
Joachim Oehler

Born in 1977, Tilman Au studied business administration, specializing in marketing and communications. Tilman Au founded New Identity AG (NIDAG) in 1998, which he developed into the largest multimedia service provider in Germany's Rhine Main area.  In 2011, he brought NIDAG into United Digital Group (UDG), which is financed by the international financial investor EQT. Since then he has acted as an angel investor.


Tilman Au is a shareholder in numerous startups in the digital media field. As founder and managing director of Startup Netzwerk Mainz e.V., a not for profit association supporting startups in the city of Mainz, he is also actively involved in the startup scene in Germany's Rhine Main area.


With Joachim Oehler, he saw through the launch of the Diva-e group, of which he is co-CEO during the integration phase.

In the last fifteen years, Joachim Oehler has worked for companies including CEDC-Mediengruppe, Thyssen Telecom, Underberg, TBWA, Saatchi&Saatchi, Nedschroef, Endemol and Pixelpark AG.

Building on this experience, since 2009 he has specialized in being an initiator for buy and build platforms in the digital industry.

To date Joachim Oehler has been involved in an initiator role in all three groundbreaking buy and build platforms in the German digital industry:

  • United Digital Group GmbH (2011)

  • PIA - Performance Interactive Alliance GmbH (2013)

  • diva-e - digital values enterprise GmbH (2015)

Philipp v. Stülpnagel

After graduating in economics and first experiences in investment banking, Philipp founded SUMO GmbH in 2011 and developed the best-known SEO agency in Germany. In 2011, he managed the M&A integration of SUMO in United Digital Group (UDG), a buy-and-build-platform backed-up by EQT. Since 2014 he acts as independent M&A advisor for private equity investors, agencies and tech companies in the digital market. In this role he was responsible for the sale of Munich-based software company Refined Labs to US competitor Visual IQ.


In 2017 Philipp joined Buy&Build Investments GmbH as Partner and supports Tilman Au and Joachim Oehler in identifying successful market player and creating new platforms.

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