Case study

Transformation in the Enterprise environment: The core banking system of Helaba

With eXplain from PKS, we were able to remove a considerable amount of code that was no longer required in our Natural and Cobol-based core banking system. eXplain enabled us to fundamentally clean up and purge the system. The documentation created fully automatically by eXplain also comprehensively meets our audit requirements. These are just two examples of how eXplain supports us in our project „stabilization of the core banking system”. I would also like to emphasize the extremely pleasant cooperation with the competent team at PKS as well as the flexible possibilities in everyday project work. Helaba-specific requirements could be taken into consideration at any time.

Stephan Böcher Group Leader Application DevelopmentLandesbank Hessen-Thüringen – Helaba

The company

Helaba, short for Landesbank Hessen-Thüringen, is a commercial bank with core regions in Hesse and Thuringia, Germany offering financial services to companies, banks, institutional investors and the public sector, both within Germany and internationally. At the same time, it is the central clearing institution and service provider for 40 percent of German savings banks. Helaba is an institution incorporated under public law. With approximately 6,300 employees and two headquarters in Frankfurt and Erfurt, the bank maintains branches in Düsseldorf and Kassel as well as offices in Berlin, Stuttgart, Munich and Muenster. On an international level, Helaba acts through branches and representative offices in Paris, London, New York, Madrid, Moscow, Shanghai, and Singapore. Frankfurter Sparkasse, the leading retail bank in the Rhine-Main region, is a wholly owned subsidiary of Helaba. The Helaba Group also comprises the online bank 1822direkt, LBS Hessen-Thüringen and WIBank. (Source: Wikipedia)

The initial situation

The core banking system at Helaba, one of the key parts of the company, has been running on an IBM Mainframe environment since 1979 and is essentially based on Adabas, Natural and Coboltechnologies. The system was continuously developed and expanded over a period of 20 years until it was more or less frozen shortly after the turn of the millennium and remained in use at this level until 2016.

As a stable backbone of Helaba it has always performed well and is currently supported by a team of 10 internal and 5 external developers. However, due to strategic considerations, the replacement of the core banking system with SAP standard software was tackled in 2016. The prevailing complexity in the system, with over 3,000 interfaces and incomplete technical and specialist documentation, was the reason why the cost of the changeover had to be put in the three-digit million range.

After only a short time, the implementation project had to be postponed to 2017 due to higher-priority regulatory project plans. At the same time, there were regulatory requirements which resulted in an acute need for action in the inventory system.

Complication and challenges

At the end of the considerations, it was clear to all those involved at Helaba that no matter where the journey with the core banking system might take us - no matter what new system is to come - there will be years of coexistence between the old and new systems. This also means that there will be a shortage of personnel and know-how that must be counteracted.

One of the most important findings was also that the step-by-step changeover to a new system, which is considered realistic, will only be possible if the existing system is simplified in terms of complexity and the over 3,000 interfaces are massively reduced or structured.

The pain points were obvious:


How to get an overview of the legacy system?

How to build up new resources to manage ongoing operations and the transition phase of 5-7 years?

How can complexity be reduced and a component-based migration to the new system be made?

The Helaba project team found central support for the solution of the problem in eXplain and in cooperation with PKS.






eXplain helps to create transparency, to penetrate the core banking system technically and professionally and thus to open up essential possibilities for the future

  • Establish a roadmap for stabilising the core banking system

  • Perform supporting analyses of data flow and object usage

  • Identify interfaces between the applications

  • To document the application interfaces with DV documentation in an audit-proof way

  • Simply transfer knowledge to new employees

  • Prepare a changeover in the best possible way, so that it can be carried out at low risk and at optimal cost


The intensive analysis of the core banking system has raised the question of whether a modernisation and restructuring of the core banking system can also be a valid option for complete replacement. The idea would be to encapsulate functionality, make it available via web services and therefore make the overall architecture more modular, technologically, flexible and efficient.

The advantages for the customer


The massive cost pressure can be reduced by safely removing ballast in the grown core banking system and by using modern technologies that save developers and architects time and money in their daily work.

Security, transparency and control over the running system are regained.

Filling the staff gap in the development team: Either internal or external resources.

Thanks to improved architecture in the legacy system, it is possible to use modern technologies on the host and be prepared for all paths into the future.
Picture Bernd Butscher

Helaba‘s requirements for eXplain were demanding and the core banking application and its interfaces very complex. Once again, we have shown that our innovative analysis technology can also optimally cover customer-specific features. The feedback on the utility value of eXplain was already clear during the introductory event, so a rollout is now planned for the entire team.

Bernd Butscher Head of Enterprise Software TransformationPKS Software GmbH

Tools and procedures

  •  eXplain - The mastermind for IBM applications
  • Software Clean-Up
  • Training and Coaching