1998 Dirk Oldenburg left private practice and joined the corporate sector:

• 1998 - 2000 Global General Counsel of Hoechst AG
• 2000 - 2002 General Counsel of Aventis (after merger of Hoechst and Rhone-Poulenc)
• 2000 - 2004 Member Management Board of Aventis Pharma AG, Frankfurt
• 2001 - 2004 Global Compliance Officer Aventis, Strasbourg
• 2001 - 2004 Chairman of the Management Board of Aventis Foundation
• 2002 - 2004 Member Supervisory Board Wacker Chemie AG
• 2002 - 2004 Member Management Board Aventis, Strasbourg 
• 2004 - 2005 General Counsel Sanofi-Aventis, Paris