Future-Proofing FS-CD: How to Transition from SAP ECC to S/4HANA (2/2)

Written By Jordy Bultman

In part 1 of this series, we explored the compelling reasons why insurers should modernize from ECC-based FS-CD to SAP S/4HANA FS-CD—citing the new functionalities and benefits such as real-time analytics, instant payments, cloud readiness, and process standardization. I also warned of the growing costs of staying on an outdated system, from surging technical debt to fragmented workflows.

Now, in this second blog, we turn to the “how” of making the move. Below, you’ll discover:

  • The Three Main Migration Paths—Brownfield, Greenfield, and Bluefield.

  • Challenges & Considerations—from legacy complexity to mandatory FI-GL planning.

  • Real-World Success Stories—leading insurers who have reaped the benefits of S/4HANA FS-CD.

  • Preparation Tasks to Ensure Success—what you can do now to ensure success.  

  • Closing Thoughts—on aligning your FS-CD processes with S/4HANA, covering housekeeping, archiving, and beyond.

If this blog triggers you, then:

Schedule a 30-Minute Discovery Call!

  • Get a tailored assessment of your FS-CD landscape.

  • Explore the best migration path (Brownfield, Greenfield, or Bluefield).

  • Learn how to minimize disruptions and maximize ROI.

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The Three Paths to S/4HANA

Every insurer’s S/4HANA journey is unique. The optimal approach typically hinges on your current landscape’s complexity (e.g., multiple source systems, technical debt), high-level business objectives, and readiness for change. If you also run a separate General Ledger—SAP or non-SAP—you’ll need to plan that upgrade (or full FI system upgrade) in parallel. This is for the reinsurers with a “Shadow Ledger”. Let’s compare your three main migration scenarios:

Brownfield: “Just Upgrade” or As-Is Conversion

  • How It Works
    A direct, “technical” upgrade that lifts your ECC FS-CD onto S/4HANA in largely the same form, preserving existing data and most custom code.

  • Best For Insurers Who:

    • Require minimal operational disruption.

    • Want to keep legacy FS-CD setups mostly intact.

    • Aim to avoid a major data-migration or re-engineering exercise.

  • Key Benefits

    • Faster timeline with minimal upheaval for business users.

    • Lower near-term risk, as processes remain familiar.

    • Historical transaction data stays available.

  • Potential Drawbacks

    • Carries forward technical debt and outdated custom developments.

    • Limited ability to exploit advanced S/4HANA features—like embedded analytics—right away.

Greenfield: A Clean-Slate Re-Implementation

  • How It Works
    A brand-new FS-CD instance in S/4HANA, redesigned for simpler processes, possibly leveraging your years of experience with ECC as lessons learned.

  • Best For Insurers Who:

    • Want to eliminate legacy complexity and code.

    • Operate multiple product lines, each requiring standardization or a “fresh start.”

    • Seek advanced analytics and automation with minimal leftover baggage.

  • Key Benefits

    • Adoption of S/4HANA’s modern data model (Universal Journal) and best practices from day one.

    • Substantial reduction in custom code, reducing maintenance overhead.

    • Incorporation of brand-new FS-CD features gleaned from prior implementations.

  • Potential Drawbacks

    • Time-consuming and capital-intensive re-implementation.

    • Data-migration loads and thorough user training required.

Bluefield: The Hybrid “Selective” Migration

  • How It Works
    Part-brownfield, part-greenfield. You keep critical, stable parts of ECC FS-CD while selectively transforming or “cleaning” those sub-processes that are outdated.

  • Best For Insurers Who:

    • Want a middle path—some modernization, but not a complete rebuild.

    • Have intricate FS-CD landscapes across policy, claims, or reinsurance.

    • Need to migrate in stages (e.g., by region or line of business) for risk mitigation.

  • Key Benefits

    • Only essential data and processes move, leaving behind “junk code.”

    • Phased approach mitigates risk while allowing incremental improvements.

    • Balances speed of Brownfield with the modernization benefits of Greenfield.

  • Potential Drawbacks

    • Upfront analysis to decide which processes to keep vs. rebuild.

    • More complex than a pure “lift-and-shift” approach. Requires a strong preparation. 

Challenges & Considerations

Migrating ECC FS-CD to S/4HANA is more than a technical step; it represents a strategic upgrade touching operations, integrations, and even the user experience. 

  1. Legacy Complexity

    • ECC-based FS-CD often harbors a tangle of custom code. Conduct a thorough code and config review—removing or simplifying old custom programs where possible.

  2. Multi-System Integrations

    • FS-CD rarely stands alone. It typically interacts with:

      • SAP Fioneer solutions (FS-PM, FS-CM, FS-ICM, FPSL etc).

      • SAP solutions (FS-RI, FI-CO etc)

      • Third-party systems (Guidewire, Sapiens, Duck Creek).

      • Mainframes or external modules in older insurance landscapes. 

    • Solidify your data flows, plan integration testing, and unify interfaces.

  3. Custom Code & Configuration

    • Some ECC enhancements may already be superseded by S/4HANA standard functionalities. Take this opportunity to retire outdated code and adopt standard best practices.

  4. Mandatory FI-GL Upgrade

    • S/4HANA centers on the Universal Journal for real-time finances. If you run a separate or shadow GL, plan that transition carefully to avoid reconciliation headaches.

Risk Mitigation Tips

  • Begin with an ECC system/process assessment to uncover code conflicts, data-quality issues, or interface dependencies.

  • Involve accounting teams from the start—especially if you’re bridging multiple finance systems.

  • Invest in robust training/change management so your staff can fully harness S/4HANA’s subledger innovations.

Preparation Tasks to Ensure Success

No matter the migration path—Brownfield, Greenfield, or Bluefield—the following steps will help:

  1. Document All Current FS-CD Processes

    • Identify each sub-process: billing, disbursements, dunning, broker statements, etc.

    • Pinpoint heavily customized steps and consider shifting them to standard S/4HANA flows.

    • Do FIT/GAP with the FI-CA Process navigator (private cloud) best practice to identify the standard S/4HANA flows. 

  2. Cleanup & Archiving

    • Decommission old or unused FS-CD objects.

    • Archive closed policies/claims for a smaller migration footprint.

    • Adhere to compliance retention rules—SAP ILM or standard FS-CD archiving objects can automate this.

  3. User Documentation & Key User Training

    • Maintain robust knowledge-transfer docs for ECC FS-CD usage.

    • Train on new Fiori-based tasks and subledger processes in S/4HANA.

  4. Stabilize & Clean Core

    • Move unneeded customization to SAP Business Technology Platform.

    • Keep FS-CD standard to ease future upgrades.

  5. Regulatory/Compliance Checks

    • Align new subledger processes with IFRS, ICS, or local GAAP changes.

    • Evaluate the SAP Best Practices for IFRS 17 if relevant.

Real-World Success Stories

Touring (Belgium) – Rapid Shift to S/4HANA

  • Situation: Touring, a Belgian mobility provider with insurance products, needed to modernize ECC FS-CD on a tight schedule.

  • Solution: Adopted a hybrid approach, carrying forward well-functioning parts while introducing new S/4HANA features.

  • Outcomes:

    • Completed in under 12 months despite challenging conditions.

    • Little downtime; frictionless integrations with external systems.

    • Greater digital agility.

  • Full Case Study: Touring’s Migration to SAP S/4HANA

a.s.r. Insurance (Netherlands) – Data Efficiency Gains

  • Situation: ECC on Oracle couldn’t cope with high transaction volumes, driving up storage/infra costs.

  • Solution: A two-phase approach: database migration to SAP HANA 2.0, followed by an upgrade to S/4HANA FS-CD.

  • Outcomes:

    • Monthly closings shrank from 12 hours to 4.

    • 50% database size reduction.

    • Real-time reporting drastically streamlined finance operations.

  • Full Case Study: Capgemini: a.s.r. Insurance’s Data Efficiency

In Closing

Whether you opt for Brownfield’s minimal disruption, Greenfield’s fresh start, or a balanced Bluefield migration, the end goal is the same: a future-proof FS-CD subledger on SAP S/4HANA. Success depends on:

  1. Thorough Planning—from code analysis to data cleanup.

  2. Solid Risk Management—coordinating with your finance teams early and often.

  3. Strategic Change Management—enabling your workforce to embrace S/4HANA’s real-time, automated environment.

By assessing your current ECC state, engaging the right stakeholders, and aligning on a roadmap, you can transition FS-CD to S/4HANA with minimal disruption—unlocking major process improvements, embedded analytics, instant payments, and the operational resilience needed to stay ahead in a fast-evolving insurance industry. For questions about FS-CD transformation paths, reach out—the gains in operational efficiency, automation, and analytics are well worth the journey. Let’s ensure your FS-CD environment is truly ready for the challenges and innovations of tomorrow.

Sources & Links


Jordy Bultman
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Future-Proofing FS-CD: Why Insurers Should Move from SAP ECC to S/4HANA Now (1 of 2)