After studying economics and graduating with a degree in business administration, Christoph Hellrung worked for one of Germany’s leading auditing firms. During this time, he passed the tax advisor exam and was mainly involved in auditing and advising companies in the energy sector. In May 2006, he moved to ENRO AG, a company in the renewable energy sector, where he headed the Controlling, Tax and Investor Relations departments as an authorized signatory. In January 2008, Christoph Hellrung was appointed to the Management Board of this company. In April 2009, he moved to LambdaNet Communications Deutschland AG as Head of Finance, Human Resources and Administration. From March 2010 until the sale of LambdaNet Communications Deutschland AG on 31 May 2011 by the parent company 3U HOLDING AG, he was Chief Financial Officer of LambdaNet Communications Deutschland AG.