In a constantly changing economic environment, existing companies often merge to form new economic entities. This can happen for different reasons. But what can be observed in most cases is that companies already have their own ERP system with which they map their business processes.

Once the most important tasks of such mergers have been completed, the question often arises as to how a uniform ERP system can be achieved for the entire company. During the preparation for the merger, considerations are usually already made, but these were on a higher strategic level. Now it’s important to create a concrete plan for implementation.

Due to the experience that we as Inwerken AG have gained in several projects of this type, we can provide our customers with comprehensive consultation regarding the concept and strategy for implementation. With our standardized approach, we offer a time- and resource-saving method to successfully implement the merger.

Requirements / Approach

It must be clarified whether there are legal hurdles that prohibit a uniform ERP system or make it very complex. Data protection plays an important role here.

An important prerequisite for a common ERP system is the harmonization of processes and master data.

It is certainly possible for each economically independent unit to map its own processes. And if there are legal requirements, it may also be unavoidable. However, care should be taken to keep the differences to a minimum. Coordinated processes later result in synergies that make it possible to centralize processes and make them more efficient.

It can also amount to a consolidation system. This means that either an existing system or a new system that is to be implemented consolidates the financial data, while the logistical and possibly also the financial processes continue to run on the existing systems.

Master data forms the heart of a company’s business processes. These are, at least in SAP, valid for an entire client and therefore for all parts of the company. Therefore, great care is required when creating or expanding the master data. As a rule, it is difficult afterwards to delete or correct master data once it has been incorrectly created.


When preparing, it is therefore important to pay attention to which processes apply to all companies and where there are differences. Which master data is required in the common system and, if necessary, used together. This information is important for various activities:

  • Data migration
  • Customizing
  • Test
  • Training

Once the coordination of master data and processes has been completed, the customizing is adjusted in the future shared system. It is important to ensure that the processes that should remain unchanged are not affected. However, if a change is unavoidable, the changes must be coordinated with everyone involved. Processes may need to be revised again.

Existing developments in the existing system as well as any newly implemented developments must be examined and tested for their impact on the planned processes after the merger.

Another important point is preparing and testing the data migration. For the master data, it must be clarified how duplicates should be avoided and how standardization should be designed. When it comes to movement data, questions arise about timing and scope.


Once all preparations have been made, the merger can be implemented.

To do this, a favourable time must be found at which the least impact on the business operations of the affected companies can be expected. However, there should also be sufficient time available to proceed with due care. There should be enough buffer for unforeseen events.

Technical adjustments, as long as they do not affect processes that should remain unchanged until the merger, can be introduced into the productive system a short time beforehand.

It is a matter of discretion as to when master data is migrated. If the time is chosen too early, the effort required for double care increases. When migrating at the same time as going live, the risks due to time pressure and dependencies increase.

A time at the end of a period is recommended for transaction data. This can be an annual or monthly financial statement. There are good arguments for and against both options.


During the first days and weeks after the merger, the processes and results should be closely monitored in order to identify errors and deviations at an early stage and take countermeasures, as is usual when major adjustments are put into production.

If the system is running stably, optimizations can begin to get the greatest possible benefit from the project.