Mainframe modernization patterns for financial services

Prima facie observation is that financial services organizations have been pioneers in adopting technology to reduce operating costs, accelerate innovation, and enhance customer experience.

For over five decades, IBM Mainframes have served as the backbone of IT infrastructure for many financial institutions, prized for their processing power, reliability, and security. Even today, 85 of the top 100 banks rely on mainframes for mission-critical workloads.

However, the rise of FinTechs and BigTechs, evolving business models, and increasing regulatory pressures are reshaping the technology landscape. Financial services firms are seeking modern platforms that offer agility, security, and scalability at lower costs. While many have begun migrating non-critical workloads to the cloud, some are also transitioning critical, user-facing applications to improve time-to-market and user experience—without compromising security. Yet, concerns around migration risks, timelines, and legacy process knowledge continue to hinder full-scale mainframe workload migration.

Challenges prompting organizations to explore alternatives include:

• Shortage of skilled mainframe professionals
• Outdated development tools and environments
• Manual DevOps processes
• Limited interoperability due to restricted access to applications and data
• Inability to unlock the value of vast mainframe-stored business data
• High operational costs

Many of these challenges are more perceived than real. A significant number of organizations have not modernized their mainframe tooling in over a decade. Since the release of IBM z13 in 2015, and subsequent versions z14 (2017), z15 (2019), z16 (2022), and z17 (2025), IBM has introduced innovations that enhance security, speed, resiliency, and hybrid cloud interoperability.

Hybrid cloud, combining public, private, and on-prem infrastructure, is now the preferred deployment model. It enables consistent development experiences, automation, and DevSecOps practices. Mainframes remain a vital part of hybrid cloud strategy, and organizations must evaluate what to migrate and what to modernize in place.

Capgemini and IBM offer a balanced approach to mainframe modernization—identifying workloads suitable for cloud migration while modernizing others in place.

Capgemini’s in-place modernization solution focuses on:

• Enhancing developer experience with modern IDEs like Eclipse and VSCode
• Accelerating delivery through DevOps pipelines integrated with tools like GitHub, Jenkins, Azure DevOps, and AWS CodePipeline
• Enabling real-time access to business logic and data via RESTful APIs using IBM z/OS Connect
• Integrating mainframe applications with cloud-native insights and data
• Unlocking event-driven data through IBM’s z Digital Integration Hub (zDIH)
• Virtualizing access to disparate data sources using IBM Data Virtualization Manager (DVM)
• Executing AI/ML models directly on mainframes using z16/z17 capabilities
• Modernizing legacy CICS/IMS interfaces with low-code/no-code platforms like Microsoft Power Platform
• Leveraging Red Hat OpenShift for hybrid cloud containerization
• Achieving end-to-end observability with IBM Instana, Turbonomic, and Watson AIOps

Capgemini has also established a Mainframe Modernization Experience Zone where clients can explore these use cases and co-develop solutions with experts.

Learn more about these modernization patterns by filling out the webform and downloading our Point of View.