Your new core banking system just went live. The migration appeared successful. Then Monday morning hits: customers can't access their accounts, transaction amounts don't match, and your reconciliation team is drowning in discrepancies. Sound familiar?
If you've ever been part of a major system migration, you've likely lived a version of this nightmare. What's worse is that this scenario isn't the exception—it's becoming the norm. A recent analysis of failed implementations reveals that organizations spend 60-80% of their post-migration effort on reconciliation and testing, yet they're doing it completely blind, without understanding WHY differences exist between old and new systems.
The result? Projects that should take months stretch into years, costs spiral out of control, and in the worst cases, customers are impacted for weeks while teams scramble to understand what went wrong.
Let's be honest about what post-migration reconciliation looks like today. Your team runs the same transaction through both the legacy system and the new system. The old system says the interest accrual is $5. The new system says it's $15. Now what?
"At this point in time, the business says who is right?" explains Caitlin Truong, CEO of Zengines. "Is it that we have a rule or some variation or some specific business rule that we need to make sure we account for, or is the software system wrong in how they are computing this calculation? They need to understand what was in that mainframe black box to make a decision."
The traditional approach looks like this:
The real cost isn't just time—it's risk. While your team plays detective with legacy systems, you're running parallel environments, paying for two systems, and hoping nothing breaks before you figure it out.
Here's what most organizations don't realize: the biggest risk in any migration isn't moving the data—it's understanding the why behind the data.
Legacy systems, particularly mainframes running COBOL code written decades ago, have become black boxes. The people who built them are retired. The business rules are buried in thousands of modules with cryptic variable names. The documentation, if it exists, is outdated.
"This process looks like the business writing a question and sending it to the mainframe SMEs and then waiting for a response," Truong observes. "That mainframe SME is then navigating and reading through COBOL code, traversing module after module, lookups and reference calls. It’s understandable that without additional tools, it takes some time for them to respond."
When you encounter a reconciliation break, you're not just debugging a technical issue—you're conducting digital archaeology, trying to reverse-engineer business requirements that were implemented 30+ years ago.
One of our global banking customers faced this exact challenge. They had 80,000 COBOL modules in their mainframe system. When their migration team encountered discrepancies during testing, it took over two months to get answers to simple questions. Their SMEs were overwhelmed, and the business team felt held hostage by their inability to understand their own system.
"When the business gets that answer they say, okay, that's helpful, but now you've spawned three more questions and so that's a painful process for the business to feel like they are held hostage a bit to the fact that they can't get answers themselves," explains Truong.
What if instead of discovering reconciliation issues during testing, you could predict and prevent them before they happen? What if business analysts could investigate discrepancies themselves in minutes instead of waiting months for SME responses?
This is exactly what our mainframe data lineage tool makes possible.
"This is the challenge we aimed to solve when we built our product. By democratizing that knowledge base and making it available for the business to get answers in plain English, they can successfully complete that conversion in a fraction of the time with far less risk," says Truong.
Here's how it works:
AI algorithms ingest your entire legacy codebase—COBOL modules, JCL scripts, database schemas, and job schedulers. Instead of humans manually navigating 80,000 lines of code, pattern recognition identifies the relationships, dependencies, and calculation logic automatically.
The AI doesn't just map data flow—it extracts the underlying business logic. That cryptic COBOL calculation becomes readable: "If asset type equals equity AND purchase date is before 2020, apply special accrual rate of 2.5%."
When your new system shows $15 and your old system shows $5, business analysts can immediately trace the calculation path. They see exactly why the difference exists: perhaps the new system doesn't account for that pre-2020 equity rule embedded in the legacy code.
Now your team can make strategic decisions: Do we want to replicate this legacy rule in the new system, or is this an opportunity to simplify our business logic? Instead of technical debugging, you're having business conversations.
Let me share a concrete example of this transformation in action. A financial services company was modernizing their core system and moving off their mainframe. Like many organizations, they were running parallel testing—executing the same transactions in both old and new systems to ensure consistency.
Before implementing AI-powered data lineage:
After implementing the solution:
"The business team presents their dashboard at the steering committee and program review every couple weeks," Truong shares. "Every time they ran into a break, they have a tool and the ability to answer why that break is there and how they plan to remediate it."
The most successful migrations we've seen follow a fundamentally different approach to reconciliation:
Before you migrate anything, understand what you're moving. Use AI to create a comprehensive map of your legacy system's business logic. Know the rules, conditions, and calculations that drive your current operations.
Instead of hoping for the best, use pattern recognition to identify the most likely sources of reconciliation breaks. Focus your testing efforts on the areas with the highest risk of discrepancies.
When breaks occur (and they will), empower your business team to investigate immediately. No more waiting for SME availability or technical resource allocation.
Transform reconciliation from a technical debugging exercise into a business optimization opportunity. Decide which legacy rules to preserve and which to retire.
"The ability to catch that upfront, as opposed to not knowing it and waiting until you're testing pre go-live or in a parallel run and then discovering these things," Truong emphasizes. "That's why you will encounter missed budgets, timelines, etc. Because you just couldn't answer these critical questions upfront."
Here's something most organizations don't consider: this capability doesn't become obsolete after your migration. You now have a living documentation system that can answer questions about your business logic indefinitely.
Need to understand why a customer's account behaves differently? Want to add a new product feature? Considering another system change? Your AI-powered lineage tool becomes a permanent asset for business intelligence and system understanding.
"When I say de-risk, not only do you de-risk a modernization program, but you also de-risk business operations," notes Truong. "Whether organizations are looking to leave their mainframe or keep their mainframe, leadership needs to make sure they have the tools that can empower their workforce to properly manage it."
Every migration involves risk. The question is whether you want to manage that risk proactively or react to problems as they emerge.
Traditional reconciliation approaches essentially accept risk—you hope the breaks will be manageable and that you can figure them out when they happen. AI-powered data lineage allows you to mitigate risk substantially by understanding your system completely before you make changes.
The choice is yours:
If you're planning a migration or struggling with an ongoing reconciliation challenge, you don't have to accept the traditional pain points as inevitable. AI-powered data lineage has already transformed reconciliation for organizations managing everything from simple CRM migrations to complex mainframe modernizations.
Schedule a demo to explore how AI can turn your legacy "black box" into transparent, understandable business intelligence.

For Chief Risk Officers and Chief Compliance Officers at insurance carriers, ORSA season brings a familiar tension: demonstrating that your organization truly understands its risk exposure -- while knowing that critical calculations still run through systems nobody fully understands anymore.
The Own Risk and Solvency Assessment (ORSA) isn't just paperwork. It's a commitment to regulators that you can trace how capital adequacy gets calculated, where stress test assumptions originate, and why your models produce the outputs they do. For carriers still running policy administration, actuarial calculations, or claims processing on legacy mainframes, that commitment gets harder to keep every year.
Most large insurers have mainframe systems that have been running -- and evolving -- for 30, 40, even 50+ years. The original architects retired decades ago. The business logic is encoded in millions of lines of COBOL across thousands of modules. And the documentation? It hasn’t been updated in years.
This creates a specific problem for ORSA compliance: when regulators ask how a particular reserve calculation works, or where a risk factor originates, the honest answer is often "we'd need to trace it through the code."
That trace can take weeks. Sometimes months. And even then, you're relying on the handful of mainframe specialists who can actually read the logic -- specialists who are increasingly close to retirement themselves.
ORSA requires carriers to demonstrate effective risk management governance. In practice, that means showing:
For modern cloud-based systems, this is straightforward. Metadata catalogs, audit logs, and documentation are built in. But for mainframe systems -- where the business logic is the documentation, buried in procedural code -- this level of transparency requires actual investigation.
Every CRO knows the scenario: an examiner asks a pointed question about a specific calculation. Your team scrambles to trace it back through the systems. The mainframe team pulls in their most senior developer (who was already over-allocated with other work). Days pass. The answer finally emerges -- but the process exposed just how fragile your institutional knowledge has become.
These fire drills are getting more frequent, not less. Regulators have become more sophisticated about data governance expectations. And the talent pool that understands legacy COBOL systems shrinks every year.
The question isn't whether you'll face this challenge. It's whether you'll face it reactively -- during an exam -- or proactively, on your own timeline.
The good news: you don't have to modernize your entire core system to solve the documentation problem. New AI-powered tools can parse legacy codebases and extract the data lineage that's been locked inside for decades.
This means:
The goal isn't to replace your legacy systems overnight. It's to shine a light into the black box -- so you can demonstrate governance and control over systems that still run critical functions.
The carriers who navigate ORSA most smoothly aren't the ones with the newest technology. They're the ones who can clearly articulate how their risk management processes work -- including the parts that run on 40-year-old infrastructure.
That clarity doesn't require a multi-year modernization program. It requires the ability to extract and visualize what your systems already do, in a format that satisfies both internal governance requirements and external regulatory scrutiny.
For CROs and CCOs managing legacy technology estates, that capability is becoming less of a nice-to-have and more of a prerequisite for confident compliance.
Zengines helps insurance carriers extract data lineage and governance controls from legacy mainframe systems. Our AI-powered platform parses COBOL code and related infrastructure to deliver the transparency regulators expect -- without requiring a rip-and-replace modernization.

LLM code analysis tools like ChatGPT and Copilot excel at explaining and translating specific COBOL programs you've already identified. Mainframe data lineage platforms like Zengines excel at discovering business logic across thousands of programs when you don't know where to look. Most enterprise modernization initiatives need both: data lineage to find what matters, LLMs to accelerate the work once you've found it.
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When enterprises tackle mainframe modernization and legacy COBOL code analysis, two technologies dominate the conversation: Large Language Models (LLMs) and mainframe data lineage platforms. Both promise to reveal what your code does—but they solve fundamentally different problems.
LLMs like ChatGPT, GitHub Copilot, and IBM watsonx Code Assistant excel at interpreting and translating code you paste into them. Data lineage platforms like Zengines excel at discovering and extracting business logic across enterprise codebases—often millions of lines of COBOL—when you don't know where that logic lives.
Understanding this distinction determines whether your modernization initiative succeeds or stalls. This guide clarifies when each approach fits your actual need.
LLM code analysis tools provide deep explanations of specific code. They rewrite programs in modern languages, optimize algorithms, and tutor developers. If you know which program to analyze, LLMs accelerate understanding and translation.
Mainframe data lineage platforms find business logic you didn't know existed. They search across thousands of programs, extract calculations and conditions at enterprise scale, and prove completeness for regulatory compliance like BCBS-239.
The overlap matters: Both can show you what calculations do. The critical difference is scale and discovery. Zengines extracts calculation logic from anywhere in your codebase without knowing where to look. LLMs explain and transform specific code once you identify it.
Most enterprise teams need both: data lineage to discover scope and extract system-wide business logic, LLMs to accelerate understanding and translation of specific programs.
The phrase "shows you how code works" means different things for each tool—and the distinction matters for mainframe modernization projects.
Traditional (schema-based) lineage tools show that Field A flows to Field B, but not what happens during that transformation. They map connections without revealing logic.
Code-based lineage platforms like Zengines extract the actual calculation:
PREMIUM = BASE_RATE * RISK_FACTOR * (1 + ADJUSTMENT)
...along with the conditions that govern when it applies:
IF CUSTOMER_TYPE = 'COMMERCIAL' AND REGION = 'EU'
This reveals business rules governing when logic applies across your entire system.
LLMs explain code line-by-line, clarify algorithmic intent, suggest optimizations, and generate alternatives—but only for code you paste into them.
The key difference: Zengines shows you calculations across 5,000 programs without needing to know where to look. LLMs explain calculations in depth once you know which program matters. Both "show how code works," but at different scales for different purposes.
The right tool depends on the question you're trying to answer. Use this table to identify whether your challenge calls for an LLM, a data lineage platform, or both.
Notice the pattern: LLMs shine when you've already identified the code in question. Zengines shines when you need to find or trace logic across an unknown scope.
Beyond specific use cases, it helps to understand how these tools differ in design and outcomes. This comparison highlights what each tool is built for—and where each falls short.
Successful enterprise modernization initiatives use both tools strategically. Here's the workflow that works:
Many teams successfully use LLMs to port known programs and assume this scales to enterprise-wide COBOL modernization. The confusion happens because:
Teams don't realize they have a system-level problem until deep into the initiative when they discover programs or dependencies they didn't know existed.
LLM code analysis and mainframe data lineage platforms solve different problems:
The critical distinction isn't whether they can show you what code does—both can. The distinction is scale, discovery, and proof of completeness.
For enterprise mainframe modernization, regulatory compliance, and large-scale initiatives, you need both. Data lineage platforms like Zengines find what matters across your entire codebase and prove you didn't miss anything. LLMs then accelerate the mechanical work of understanding and translating what you found.
The question isn't "which tool should I use?", it's "which problem am I solving right now?".
If you're planning a mainframe modernization initiative, regulatory compliance project, or enterprise-wide code analysis, we'd love to show you how Zengines works alongside your existing LLM tools.
Schedule a demo to see our mainframe data lineage platform in action with your use case.
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For nearly a decade, global banks have treated BCBS 239 compliance as an aspirational goal rather than a regulatory mandate. That era is ending.
Since January 2016, the Basel Committee's Principles for Effective Risk Data Aggregation and Risk Reporting (BCBS 239) have required global systemically important banks to maintain complete, accurate, and timely risk data. Yet enforcement was inconsistent, and banks routinely pushed back implementation timelines.
Now regulators are done waiting. According to KPMG, banks that fail to remediate BCBS 239 deficiencies are "playing with fire."
At the heart of BCBS 239 compliance sits data lineage - the complete, auditable trail of data from its origin through all transformations to final reporting. Despite being mandatory for nearly nine years, it remains the most consistently unmet requirement.
From 2016 through 2023, comprehensive data lineage proved extraordinarily difficult to verify and enforce. The numbers tell the story: as of November 2023, only 2 out of 31 assessed global systemically important banks fully complied with all BCBS 239 principles. Not a single principle has been fully implemented by all banks (PwC).
Even more troubling? Progress has been glacial. Between 2019 and 2022, the average compliance level across all principles barely moved - from 3.14 to 3.17 on a scale of 1 ("non-compliant") to 4 ("fully compliant") (PwC).
Throughout this period, banks submitted implementation roadmaps extending through 2019, 2021, and beyond, citing the technical complexity of establishing end-to-end lineage across legacy systems. Many BCBS 239 programs were underfunded and lacked attention from boards and senior management (PwC). For seven years past the compliance deadline, data lineage requirements remained particularly challenging to implement and even harder to validate.
The Basel Committee's November 2023 progress report marked a shift in tone. Banks' progress was deemed "unsatisfactory," and regulators signaled that increased enforcement measures - including capital surcharges, restrictions on capital distribution, and other penalties would follow (PwC).
Then came the ECB's May 2024 Risk Data Aggregation and Risk Reporting (RDARR) Guide, which provides unprecedented specificity on what compliant data lineage actually looks like - requirements that were previously open to interpretation (EY).
In public statements, ECB leaders have hinted that BCBS 239 could be the next area for periodic penalty payments (PPPs)—daily fines that accrue as long as a bank remains noncompliant (KPMG). These penalties can reach up to 5% of average daily turnover for every day the infringement continues, for a maximum of six months (European Central Bank).
This enforcement mechanism is no longer theoretical. In November 2024, the ECB imposed €187,650 in periodic penalty payments on ABANCA for failing to comply with climate risk requirements—demonstrating the regulator's willingness to deploy this tool (European Banking Authority).
European enforcement now includes ECB letters with findings, Pillar 2 requirement (P2R) add-ons, and fines (McKinsey & Company). These aren't hypothetical consequences.
ABN AMRO's Pillar 2 requirement increased by 0.25% to 2.25% in 2024, with the increase "mainly reflecting improvements required in BCBS 239 compliance" (ABN AMRO). That's a tangible capital cost for risk data aggregation deficiencies.
The ECB's May 2024 RDARR Guide goes further, warning that banks must "step up their efforts" or face "escalation measures." It explicitly states that deficiencies may lead to reassessment of the suitability of responsible executives—and in severe cases, their removal (EY).
American regulators have demonstrated equal resolve on data management failures. The OCC assessed a $400 million civil money penalty against Citibank in October 2020 for deficiencies in data governance and internal controls (Office of the Comptroller of the Currency). When Citi's progress proved insufficient, regulators added another $136 million in penalties in July 2024 for failing to meet remediation milestones (FinTech Futures).
Deutsche Bank felt the consequences in 2018, failing the Federal Reserve's CCAR stress test specifically due to "material weaknesses in data capabilities and controls supporting its capital planning process"—deficiencies examiners explicitly linked to weak data management practices (CNBC, Risk.net).
The ECB's May 2024 RDARR Guide exceeds even the July 2023 consultation draft in requiring rigorous data governance and lineage frameworks (KPMG). The specificity is unprecedented: banks need complete, attribute-level data lineage encompassing all data flows across all systems from end to end—not just subsets or table-level views.
The ECB is testing these requirements through on-site inspections that typically last up to three months and involve as many as 15 inspectors. These examinations often feature risk data "fire drills" requiring banks to produce large quantities of data at short notice with little warning (KPMG). Banks without comprehensive automated data lineage simply cannot respond adequately.
The regulatory stance continues to intensify. The ECB has announced targeted reviews of RDARR practices, on-site inspections, and annual questionnaires as key activities in its supervisory priorities work program (EY). With clearer guidance on what constitutes compliant data lineage and explicit warnings of enforcement escalation, deficiencies that were difficult to verify in previous years have become directly testable.
BCBS 239 data lineage requirements are mandatory and now explicitly defined in regulatory guidance. But here's the uncomfortable truth: for most banks, the biggest gap isn't in modern cloud systems with well-documented APIs. It's in the legacy mainframes that still process the majority of core banking transactions.
These systems—built on COBOL, RPG, and decades-old custom code—are the "black boxes" that make BCBS 239 compliance so difficult. They hold critical risk data, but their logic is buried in thousands of modules written by engineers who retired years ago. When regulators ask "where did this number come from?", banks often cannot answer with confidence.
Zengines' AI-powered platform solves this specific challenge. We deliver complete, automated, attribute-level lineage for legacy mainframe systems - parsing COBOL code, tracing data flows through job schedulers, and exposing the calculation logic that determines how risk data moves from source to regulatory report.
This isn't enterprise-wide metadata management. It's targeted, deep lineage for the systems that have historically been impossible to document—the same systems that trip up banks during ECB fire drills and on-site inspections. Zengines produces the audit-ready evidence that satisfies examination requirements, with the granularity regulators now explicitly demand.
For banks facing P2R capital add-ons, the cost of addressing mainframe lineage gaps is minimal compared to ongoing capital charges for non-compliance - let alone the risk of periodic penalty payments accruing at up to 5% of daily turnover.
BCBS 239 has required comprehensive data lineage since January 2016. With the May 2024 RDARR Guide providing explicit requirements and regulators signaling enforcement escalation, banks can no longer defer implementation—especially for legacy systems.
Zengines provides the proven technology to shine a light into mainframe black boxes, enabling banks to demonstrate compliance when regulators arrive with data requests and their enforcement toolkit.
Learn more today.
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