U.S. enterprises adopt GenAI for mainframe modernization and cloud migration

U.S. enterprises are increasingly adopting GenAI-based services to modernize mainframe workloads and support cloud migration, according to a new report from Information Services Group. The 2025 ISG Provider Lens report highlights how these services reduce both costs and development time.

The report, focused on mainframe services for the U.S. and Brazil, notes that while companies have not yet deployed Generative AI (GenAI) applications directly on mainframes, many utilize GenAI tools to enhance coding efficiency. This shift allows organizations to expedite modernization processes by leveraging advanced capabilities in code inspection, documentation, and testing.

John Schick, ISG's consulting lead on mainframe computing, emphasized that the fundamental functions of mainframes remain critical for enterprises. GenAI tools enable service providers to explore new strategies for maximizing mainframe value.

Some U.S. organizations are opting to reengineer software instead of the popular strategy of replatforming to the cloud, due to enhanced efficiencies provided by GenAI. Previously, enterprises largely focused on preserving legacy Application functionality, but shifting expectations now encourage innovations that contribute additional value.

Brazilian firms, particularly within banking and retail, experience similar modernization pressures. Banco Itaú Unibanco plans to complete its migration to AWS by 2028, reflecting the broader trend of increasing demand for modernization solutions in Brazil.

Furthermore, U.S. companies maintaining mainframe systems benefit from improved optimization services through GenAI. Many adopt DevOps practices, utilizing containers and APIs to enhance development and compliance measures. GenAI tools also expedite the discovery of necessary code alterations in legacy systems.

As part of the report, ISG identified numerous vendors enhancing their mainframe Application software with GenAI capabilities. Although large language models struggle with specific Application architectures, they aid in faster code development through various assessment and refactoring tools.

Jan Erik Aase, partner and global leader at ISG, noted that GenAI mitigates risks associated with mainframe migration, allowing enterprises to consider their mainframe futures with reduced apprehension.

The report also discusses trends in mainframe operations, including the continued rise of mainframe as a service outsourcing, which underscores the evolving landscape of Enterprise IT.

For detailed insights into mainframe modernization challenges and strategies in the U.S. and Brazil, the report is available for purchase and provides comprehensive evaluations of 54 providers across multiple service quadrants.