Led by the Interim Manager of the Year 2025 – efficient, structured and future-ready
The Starting Point: Digital Transformation in Finance
Digital transformation continues to present growing challenges for finance and accounting departments. To meet increasing demands for efficiency, transparency, and compliance, a client of Grant Thornton decided to implement SAP S/4HANA as a modern ERP system.
The existing IT infrastructure was outdated and composed of heterogeneous systems, including DATEV for accounting. This fragmented landscape resulted in inefficiencies, high manual effort, and poor system integration. Additional challenges included inconsistent data, limited automation, and difficulties in reporting.
The goal was clear: migrating to SAP S/4HANA would enable fully integrated, automated, and transparent accounting processes.
Interim Management for a Successful Migration
The project was implemented in a targeted and efficient manner with a highly qualified interim manager from HANSE Interim’s pool of experts.
Our specialist not only brought extensive SAP S/4HANA expertise to the table, but also the necessary industry knowledge and strategic experience to optimize the migration process.
Interim Manager René Karrasch was named Interim Manager of the Year at the AIMP Annual Forum 2025 for his outstanding performance.
The jury particularly recognized his ability to implement complex ERP migrations in a structured, secure and sustainable manner, as impressively demonstrated in this project.
Particularly impressive was not only the professional excellence, but also the way in which René Karrasch managed this project: with calm, with vision and with a trusting cooperation with the client, Grant Thornton, the teams on site and HANSE Interim as provider.
The Challenge: Fragmented Systems Slowed Down Efficiency
The main task was to migrate the customer’s financial accounting from a fragmented legacy system to a fully integrated SAP S/4HANA solution.
The following requirements had to be met:
1. data migration:
2. process integration & automation:
3. Test management & system validation:
4. compliance & audit:
5. go-live & stabilization:
The Solution: A Structured Four-Step Approach
The following measures were taken to ensure the successful migration to SAP S/4HANA:
Step 1: Analysis and Preparation
• Assessment of existing processes and systems
• Data cleansing and validation
• Defining the migration strategy including mapping from DATEV to SAP S/4HANA
Step 2: Implementation and Testing
• Development and execution of test plans for all relevant processes
• SAP S/4HANA configuration and customization
• Ensuring intercompany reconciliations and tax compliance
Step 3: Training and Change Management
• Training of staff and accounting teams
• Documentation of new accounting processes
Step 4: Go-Live and Stabilization
• Support during go-live and real-time guidance
• Monitoring of initial closings
• Fine-tuning and continuous improvement
The Result: More Efficiency, Less Complexity
The SAP S/4HANA migration provided multiple benefits:
Successful data migration:
- All DATEV data was transferred to SAP S/4HANA completely and without errors.
- External auditors have certified the migration.
Process automation & increased efficiency:
- Monthly and annual financial statements were significantly accelerated.
- Automated tax calculation and simplified advance VAT returns.
- Digitization of invoice processing and accounting processes.
Improved data integrity & transparency:
- Centralized data storage enabled faster and more accurate reports.
- Group reporting was improved and intercompany reconciliations simplified.
Smooth go-live & stable operation:
- The implementation was stable and without significant disruption to day-to-day operations.
- The accounting teams were able to work quickly and efficiently with the new system
Conclusion: Successful transformation through targeted interim management
Conclusion: Successful transformation through targeted interim management
The introduction of SAP S/4HANA was a strategic success for Grant Thornton’s client. The combination of detailed planning, extensive testing and a structured change management approach enabled an error-free migration and an efficient go-live.
The new automated processes have contributed to significant efficiency gains, transparency and compliance improvements. The finance and accounting department is now future-proof and benefits from the advantages of a modern ERP platform.
The successful implementation with an experienced interim manager from HANSE Interim demonstrated that a well-planned and executed SAP S/4HANA transformation can make a significant contribution to business optimization.
This shows that targeted interim management not only accelerates digitalization, but also secures sustainable competitive advantages.
With best regards
Your HANSE Interim Management
Andreas Lau
