Welcome on the DDIM-Website of Siegfried Lettmann!

I am an experienced interim manager at executive level with a focus on transformation in sales. As managing director or division manager, I temporarily take over the company management, sales and marketing as well as product management - also in an international context.

I differentiate myself through experience, quality and methodology - with excellent customer references and awards, e.g. as Interim Manager of the Year and with the Interim Management Excellence Award.


  • Sales and Growth
  • Digitlization in Sales and Marketing
  • Business Model Innovation and Development
  • Customer Segment Management
  • Key Account Management
  • Innovation Management
  • Agile Leadership and Executive Development