Sony Bank and Fujitsu are applying generative AI at full scale in the development of Sony Bank’s core banking system.
By establishing a mechanism for AI to utilize development assets such as design documents, source code, and test assets, and gradually expanding its application to key processes from design to manufacturing and testing through actual development, the companies have confirmed a 30% reduction in the development period from basic design to integration testing as of July 2026, compared to conventional methods.
The system adopts Fujitsu’s core banking solution, Fujitsu Core Banking xBank, which features a cloud-native architecture operating on Amazon Web Services (AWS), providing an environment that enables rapid integration and trials with generative AI services. This environment allowed for the phased application of generative AI to each process.
In this initiative, an AI agent centered on Anthropic PBC’s Claude on Amazon Bedrock is utilized across processes, with human oversight for final judgment and quality assurance.
The use of generative AI is not limited to proof-of-concept (PoC) but has been established as a development process for a core banking system in live operation.
Sony Bank and Fujitsu will leverage the knowledge and development assets gained from this initiative to other processes and systems, further deepening and expanding the use of generative AI at Sony Bank.
Fujitsu will also apply the knowledge gained from this initiative to future Core Banking xBank development and development for other financial institutions, contributing to the advancement of financial system development.
In this initiative, generative AI transforms the entire development process by leveraging design documents, source code, and test assets across all stages.
This initiative has resulted in a 40% reduction in man-hours and a 30% reduction in development period for processes from basic design to integration testing.
Specifically, the companies confirmed up to a 90% reduction in impact assessment man-hours in the basic design phase, up to a 40% reduction in design document creation man-hours in the detailed design phase, a 99% source code generation rate in the implementation phase, and up to a 90% reduction in test execution man-hours in the integration testing phase.
Sony Bank and Fujitsu intend to proceed with the application of generative AI to the entire development process, including requirements definition, and gradually expand its application to security, operations, and maintenance areas.
Further, the knowledge and development assets gained from this initiative will be utilized in peripheral systems, further deepening and expanding the use of generative AI at Sony Bank.
Sony Bank aims to become an “AI-native bank” that can quickly respond to changing customer needs and business environments by continuously utilizing AI.
Also, Fujitsu plans to extend this model to other financial institutions adopting Core Banking xBank, supporting the broader modernization of banking systems in Japan.
The knowledge and feedback gained from this initiative will also be utilized in the development of the Uvance for Finance AI Transformation Platform, a dedicated AI platform that supports AI utilization for financial institutions, aiming for further sophistication of AI-driven system development.
Additionally, through Uvance for Finance, which enhances financial operations with data and AI, Fujitsu will accelerate system development for financial institutions and advance the continuous transformation of financial services.
Tatsuya Fukushima, executive officer at Sony Bank, said that the successful full-scale application of generative AI to the development of our production core banking system is a significant step towards becoming a bank that continuously evolves based on AI.
“We will continue to promote our evolution into an AI-native bank while ensuring safety and quality through collaboration with Fujitsu, AWS Japan, and Anthropic,” said Fukushima.
Masaru Yagi, EVP at Fujitsu, said that Fujitsu is promoting the provision of Core Banking xBank as a mission-critical foundation that supports the transformation of financial institutions.
“This initiative is an advanced example of the full-scale application of generative AI to the actual development of a core banking system on Core Banking xBank, demonstrating a new model for financial system development,” said Yagi.
