Transformation Options for SAP in a Post-Merger Environment

In the dynamic environment of mergers and acquisitions, companies that have recently undergone a merger face the critical task of selecting the right future ERP solution and processes to support their operating models. This decision is pivotal in ensuring the seamless integration of systems, processes and the realisation of synergies. One of the options for companies running SAP ECC is transitioning to SAP’s S/4HANA® digital core catalysing the harmonization process. This transition can be approached in various ways, each offering unique benefits and challenges.

Migration paths to SAP S/4HANA

Companies considering their future digital core solution in a post-merger environment have a spectrum of possibilities to transition to SAP S/4HANA®:

• Greenfield Approach: Historically preferred by organisations with less fit-for-purpose legacy solutions, this approach involves a complete overhaul of the existing system. It is ideal for companies looking to genuinely transform their businesses and deliver tangible benefits and is perfect in a post-merger context to redesign the merged company with no legacy technical debt. However, these programmes tend to be longer, extending the 'time to value' compared to other options.
• Brownfield Technical Conversions: This approach is quicker but often yields minimal initial business benefits beyond keeping ERP software on a supported release. It requires pre-requisite projects ahead of the conversion and can necessitate expensive post-conversion data clean-up projects. Considering pre- and post-conversion activities, these programmes may be longer and costlier than initially expected, potentially constraining the benefits the SAP S/4HANA® solution can deliver. 
• Selective Transformation: Increasingly adopted by companies who are merging or adapting to new business models, this approach focuses on modernising specific aspects of the existing SAP ECC system to better serve the business, drive efficiency, or reduce costs. It allows companies to retain valuable assets built into their legacy SAP ECC systems while removing redundant code and embracing digital possibilities with an optimised investment level. In a post-merger context, it allows legacy entities to mix-and-match the best of their functionalities.

The best of both worlds

Greenfield transformations or Selective Transformation techniques for Post-Merger companies should consider the following points:Preservation of Existing Investments:

Companies can selectively transform business processes to drive standardisation and simplification across the business.

• Adoption of Innovations: Through a roadmap of agile projects, companies can adopt SAP S/4HANA® innovations at a pace driven by business priorities, benefits, and the ability to absorb change.
• Time to Initial Value: Selective Transformation techniques can enhance Greenfield transformations and provide more initial benefits than Brownfield conversions.
• Simplified and Standardised ERP: Deploying a simplified and standardised SAP S/4HANA® ERP helps achieve a “Clean Core” objective, reducing data footprint, saving license costs, and improving data quality for better analytics and decision-making.
• Avoidance of Pre-requisite Projects: Companies can avoid a range of pre-requisite projects on their SAP ECC system, such as Customer Vendor Integration, migration to New G/L, and data archiving.
• Streamlined Demand for Resources: Build trust and momentum needed to support further post-migration innovation projects.Self-funding Programmes: Benefits realised from early go-lives help fund subsequent innovation projects, smoothing cash flows.

Transformation Approaches reusing legacy solutions

• Mix and Match: Ideal for companies needing significant process transformation and benefits with the initial go-live. This approach starts with a Greenfield SAP S/4HANA® system into which configuration and custom code from the converted ECC system are selectively brought across. Additional processes and configuration are then built upon to deliver the desired transformational solution.
• Other Considerations: In a post-merger environment, both Greenfield and Selective Transformation requires thoughtful planning of which elements of the legacy ECC solution should be migrated, remediated, or transformed. Understanding the implications and complexities related to data, configuration, custom code, and integrations is critical to developing a robust implementation plan. Additionally, companies should consider how much historical data to migrate and in which areas.

Deloitte Technology Trends – Core Modernisation

For further insights into the latest technology trends and how they can
impact your ERP transformation journey, refer to Deloitte's Technology Trends report for 2025, specifically the sections on Core Modernization and the influence of Artificial Intelligence. This year’s reports provide valuable
information on emerging technologies and their potential to drive innovation and efficiency in business processes. The full report can be downloaded at Deloitte Technology Trends 2025.