Executive Summary
Mizuho Financial Group is one of Japan's three "mega-bank" financial groups and one of the largest financial institutions in the world. Headquartered in Tokyo, Mizuho operates across corporate banking, retail banking, investment banking, asset management, and securities — serving millions of customers through a global network spanning Asia, the Americas, and Europe. With over 60,000 employees and total assets exceeding ¥250 trillion (approximately $1.7 trillion USD), Mizuho is a systemically important financial institution (SIFI) subject to the most stringent regulatory requirements in the global banking sector.
For decades, IBM mainframe infrastructure has served as the critical foundation for Mizuho's core banking operations. The bank's z/OS-based systems process millions of transactions daily — including real-time payments, securities clearing, trade finance, foreign exchange, and regulatory reporting. Mainframe downtime is not an option. The consequence is that mainframe modernisation moves at a deliberate pace, and IBM licensing costs accumulate accordingly.
Redress Compliance was engaged to conduct a comprehensive review of Mizuho's IBM mainframe licensing position. Over 16 weeks, the engagement delivered $71 million in verified IBM z/OS mainframe licensing and support savings through MLC cost optimisation, workload realignment, LPAR reconfiguration, and strategic contract restructuring — with zero operational disruption.
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Tell Us Your Situation →The Challenge: IBM Mainframe Licensing in a Global Mega-Bank
IBM mainframe licensing for a global financial institution of Mizuho's scale involves a level of complexity that IBM's standard account management cannot effectively navigate on the customer's behalf. Monthly Licence Charges (MLC) for z/OS and associated IBM software are calculated based on peak Rolling 4-Hour Average (R4HA) processor utilisation — a metric that rewards careful workload management but penalises institutions that have not optimised their LPAR configurations and workload distribution.
MLC pricing mechanics. IBM's MLC pricing is opaque by design. Pricing is calculated on a machine-by-machine basis, with peaks measured hourly using the R4HA methodology. For a bank of Mizuho's scale — with multiple mainframe environments spanning Japanese domestic operations, global banking platforms, and disaster recovery infrastructure — the interaction between workloads, LPAR configurations, and MLC caps creates optimisation opportunities that require deep technical expertise to identify and execute.
Legacy workload accumulation. Over decades, Mizuho had accumulated z/OS workloads from multiple legacy systems, acquired entities, and successive technology programmes. Some workloads were running on mainframe capacity that exceeded current requirements. Others were candidates for workload management adjustments that would reduce peak R4HA measurements without operational impact.
Contract structure complexity. Mizuho's IBM mainframe contracts had evolved across multiple renewal cycles and negotiations, creating a fragmented contract structure with varying MLC caps, software subscription terms, and support commitments across different CEC configurations. No single internal team had full visibility across the entire mainframe contract estate.
The Engagement: 16-Week Structured Programme
Phase 1 — Mainframe Licensing Audit (Weeks 1 to 4)
Comprehensive audit of Mizuho's IBM z/OS licensing position across all mainframe environments. This included a full inventory of all CEC configurations and LPAR structures, analysis of peak R4HA measurements and their contribution to MLC costs, review of all IBM mainframe contracts, MLC caps, and software subscription agreements, identification of workloads running at sub-optimal configurations from a licensing perspective, and benchmarking of Mizuho's MLC cost structure against comparable financial institutions. The audit established a complete baseline picture of Mizuho's mainframe licensing position — the first time this had been achieved across all environments simultaneously.
Phase 2 — Optimisation Modelling (Weeks 5 to 9)
With the baseline established, the second phase modelled the potential savings from each category of optimisation — prioritised by savings potential, implementation complexity, and operational risk. LPAR reconfiguration opportunities were identified across multiple CEC environments where workload distribution was suboptimal for MLC purposes. Workload realignment opportunities — moving specific workloads to time-shifted processing windows to reduce peak R4HA measurements — were modelled against operational constraints. MLC cap restructuring opportunities were identified where existing contractual cap structures could be renegotiated to better reflect the optimised workload profile. Sub-capacity licensing opportunities for z/OS software components were quantified. Each opportunity was modelled with a conservative and an optimistic savings estimate, and prioritised by the risk-adjusted return.
Phase 3 — Implementation (Weeks 10 to 14)
Implementation was phased to ensure zero operational disruption — a non-negotiable constraint for a systemically important financial institution processing real-time transactions 24 hours a day, seven days a week. LPAR reconfigurations were implemented in a planned maintenance window sequence. Workload realignment changes were tested in non-production environments before production implementation. All changes were validated against regulatory requirements before execution. IBM contract restructuring negotiations ran in parallel, with Redress Compliance providing direct negotiation support based on the validated optimisation data.
Phase 4 — Validation and Governance (Weeks 15 to 16)
Post-implementation verification of MLC savings against modelled projections, with full documentation of the optimised configuration for ongoing governance. The governance framework included ongoing R4HA monitoring procedures, an annual mainframe licensing review process, and a change management protocol ensuring that future workload additions are assessed for MLC impact before implementation.
Results: $71M in Verified Savings
Key Takeaways for Mainframe IBM Customers
Mizuho's $71M in mainframe savings demonstrates that large, complex IBM mainframe estates carry substantial optimisation potential — even when the customer has sophisticated internal IT teams and has been managing the mainframe environment for decades. The savings opportunity in mainframe MLC pricing is primarily a consequence of IBM's pricing model complexity and the way workload accumulation outpaces optimisation efforts over successive technology cycles.
For global financial institutions running IBM z/OS infrastructure, the question is whether internal teams have the mainframe licensing expertise, IBM contract knowledge, and negotiating leverage to identify and extract the available savings. In virtually every case, an independent IBM mainframe advisor delivers outcomes that internal negotiation cannot match — because IBM's commercial team is optimised to protect IBM's revenue, not to help customers reduce it.
For further guidance on IBM mainframe licensing strategy and MLC optimisation, see our IBM Knowledge Hub. For IBM advisory services, visit our IBM Advisory Services page. To discuss your mainframe licensing situation, contact our advisory team or explore our IBM licensing assessment tools.
Related Resources
- IBM Advisory Services
- IBM Licensing Knowledge Hub
- IBM ELA Renewal Advisory
- IBM Audit Defence Kits
- IBM Licensing Benchmarking