Core Banking system

The core banking system is the ledger of a bank. The core banking system opens and closes accounts, books every payment, interest charge and fee, runs loan and deposit contracts and delivers the figures for the balance sheet and for regulatory reports. Online banking, the mobile app, the branch desk and the payment interfaces sit on top of it and send their orders to it.

Many of these systems were written decades ago, often in COBOL for mainframes, and have been extended ever since. A modernization therefore takes years: The bank moves products and customer data to the new platform in waves and runs old and new side by side until the last wave is through. The data migration is the riskiest step, because every account and every posting history has to arrive complete while the bank keeps booking payments each day.

German banking has three pillars: savings banks, cooperative banks and private banks. The savings and cooperative banks each share one core banking system. Finanz Informatik, with its head office in Frankfurt, runs OSPlus for the Sparkassen-Finanzgruppe and describes it as a single overall banking solution built around a core banking system (in German). The Volksbanken and Raiffeisenbanken use agree21 from Atruvia, formerly Fiducia & GAD IT. At the end of 2019, after three years of serial migration, 341 cooperative banks with about 21.5 million customer accounts were on this one system (in German).

Private banks mostly run their own platforms or buy one on the market. When Deutsche Bank moved the Postbank customers onto its own IT platform in 2023, customers ran into blocked online banking and long waits for service. BaFin appointed a special representative at Deutsche Bank on 29 September 2023, to watch how the bank cleared the backlog in the retail business of Postbank and DSL Bank.

Since 17 January 2025, the Digital Operational Resilience Act (DORA) applies directly to German banks. A core banking system supports what DORA calls critical or important functions. The bank records the contract in its register of information, tests the system's resilience, reports major ICT incidents and keeps an exit strategy for the provider. BaFin supervises these duties under DORA in Germany (in German).

DORA also puts large ICT providers under direct EU oversight. On 18 November 2025, the European Supervisory Authorities published the first list of critical ICT third-party providers. Next to the big cloud providers it names software companies whose products run core banking and treasury systems at many banks, among them SAP, Oracle and FIS. A bank that runs its core on such a provider keeps its own DORA duties, and the supervisory authorities now also examine the provider directly.

AI in banking in Germany works with the data the core banking system holds, for example account and repayment histories for fraud checks and credit scoring. A model that scores the creditworthiness of a person is high-risk under the EU AI Act, with duties on data quality and human oversight.

A tokenized deposit is a bank deposit recorded on a distributed ledger, and the bank has to keep the ledger and its core banking system in step so the customer sees one balance. On 21 September 2026, the Eurosystem launched Pontes, which links DLT platforms with its TARGET Services so wholesale DLT transactions can settle in central bank money. Thirteen banks and four DLT operators had completed onboarding at the start.

Finance Loop is the meeting place for people who run and change bank IT in Germany, from core banking teams and the compliance staff who answer for DORA to the fintechs that connect to a bank's core. Finance Loop connects the finance, IT and AI communities in Germany, Austria and Switzerland, with events in Frankfurt, Munich, Berlin and Hamburg.

DZ BANK, the central institution of the cooperative banks, is one of the event and network partners of Finance Loop. Sopra Steria, which names the Sparkassen-Finanzgruppe and the cooperative banking group among its banking clients, organized fAInance, an AI conference for financial institutions in Frankfurt that Finance Loop announced. At the Frankfurt Forum on Digital Assets & Applications, the Deutsche Bundesbank, Deutsche Bank, Commerzbank and DZ Bank discussed payments in DLT-based markets. Finance Loop also presented an official side event of AI Week Frankfurt 2025 with talks on AI against financial crime and on AI testing.

A core banking system is the central software of a bank. The core banking system keeps customer accounts, books payments, interest and fees, runs loan and deposit contracts and feeds accounting and regulatory reporting.

Most Sparkassen use OSPlus from Finanz Informatik, and the Volksbanken and Raiffeisenbanken use agree21 from Atruvia. Private banks and the German branches of foreign banks run their own systems or products bought on the market.

Every account, contract and posting history has to move without a gap while the bank keeps booking payments. Banks move customers in waves, test each wave against the old system and keep both running until the last wave is done. The Postbank migration of 2023 shows the cost of problems after the switch: BaFin sent a special representative to Deutsche Bank.

Core banking comes up at Finance Loop events on digital banking, AI and DORA in Frankfurt, Munich, Berlin and Hamburg, and at Frankfurt Digital Finance, a conference Finance Loop partners with. The calendar above lists dates for these events on banking topics.