IBM’s stock dropped 13% the day Anthropic announced a COBOL translation tool. The COBOL crisis is significant, but a translation tool is not the entire solution. It’s a part of a larger effort to preserve the efficacy of these critical systems while also having qualified operators.
Jeana Bolanos · President, SalesE
When Anthropic published a blog post about an AI tool capable of translating COBOL into Java or C++, IBM’s stock fell 13% in a single session. The market had read the headline and drawn a conclusion: the COBOL problem had a path to resolution. An old language that can be into a new language.
That conclusion was wrong. And the organizations running COBOL systems (think banks, insurers, government agencies, distributors and manufacturers) whose daily operations depend on them understand why.
The COBOL problem is not a language problem. In fact, it’s the intricacies of the language that have kept it around and functioning in the most critical facets of our lives. It’s a challenge of scale and operational complexity.
The challenge of scale and retirement
COBOL is the operational backbone of the global economy. Seventy percent of the world’s critical business data runs on COBOL systems. Ninety-five percent of ATM transactions touch COBOL. More than $3 trillion in daily commerce flows through systems written in a language that was designed in 1959.
70%
of critical world business data runs on COBOL systems
58
Average age of a COBOL developer, per IBM
These systems are still running because they work with a reliability that most modern systems cannot match. IBM data shows COBOL mainframes achieve 99.999% uptime. That is roughly five minutes of unplanned downtime per year. For a bank processing millions of transactions daily, that is necessary.
There is no problem with the technology, the challenge is the number of people who understand it. According to IBM, the average COBOL developer is 58 years old. Roughly 10% of the remaining workforce retires every year. There are no meaningful educational pipelines replacing them. When those developers retire, they take with them something no translation tool can recover: a deep, intuitive understanding of how the system operates.
When the last COBOL developer retires, they take decades of undocumented system knowledge with them.
Why “just convert the code” misses the point
Most people assume that translating COBOL into a modern language like Java or Python is fundamentally a language problem. Swap the syntax, keep the logic. But it’s significantly more complex than that. At a scale that is difficult to comprehend. COBOL and modern languages are built on different assumptions about how computers handle numbers, memory, and data. In financial and transactional systems (like distribution), this would be the difference between a system that works and one that works well enough to hide very small variances (which at scale would become very large).
Start with math. COBOL was designed from the ground up for business arithmetic. Every number in a COBOL system is stored and calculated exactly as it appears ($1.10 is $1.10) not a binary approximation that rounds differently. Java’s default numeric types use a different approach that cannot represent many common decimal values exactly. Think of it like trying to write 1/3 as a decimal. You can’t do it precisely, you just get 0.333333 going on forever. Across millions of calculations, those tiny imprecisions accumulate. Java has a workaround, but it must be used deliberately and consistently by every developer who touches the code. Miss it once and you have introduced an error that would not appear in any error log. It would produce slightly incorrect numbers.
When developers at the IRS attempted to rewrite a critical COBOL system, the COBOL programmers told them plainly: the new code couldn’t do the calculations right. This example is best case, where the IRS identified the deficiency prior to making any changes. Anyone in the distribution space has seen many companies move away from COBOL systems and migrate to newer systems and in the process, lost months of revenue, man-years of time invested, not to mention millions of dollars in platform and consultant fees.
Then there is predictability. COBOL allocates memory in a fixed, predetermined way. The system behaves identically every time it runs. Modern languages like Java manage memory dynamically, periodically pausing to clean up unused data in a process that cannot be scheduled or predicted. In a system processing hundreds of thousands of transactions per hour, an unplanned pause is a real operational risk that does not exist in COBOL.
Combine math and predictability with 30 or 40 years of production operation and you have a system that is extremely challenging to replicate. Every edge case a COBOL system has ever encountered has been handled correctly and is embedded deep in the code. None of which is typically written down in operating documentation. It is encoded in the behavior of a system that has been tested by decades of transactions.
Finally, COBOL systems don’t run in isolation. They sit at the center of ecosystems that feed downstream reporting tools, receiving upstream inputs, producing output files that other applications have read in the same format for twenty years. A translated system that produces subtly differently formatted output can send downstream errors to the systems that depend on it.
This is why code conversion is an interesting capability and an incomplete solution. The language is not the problem. The problem is that most organizations cannot fully describe what their COBOL system does in day-to-day operations.
A path to a solution
The best place to start is characterization. Build a complete, validated understanding of what the system does before deciding what to do with it. That understanding is the asset. The code is just the current container.
At SalesE, we call this the Legacy Intelligence Framework. It has four phases, each a prerequisite for the next.
| SalesE Legacy Intelligence Framework — Four Phases | |||
| Phase 01 Characterize Exhaustive test coverage maps the static system. Every input, output, rule, and exception is documented with no change to the code base. | Phase 02 Validate Operational testing confirms the system’s behavior against documented expectations. Edge cases and undocumented logic are surfaced and recorded. | Phase 03 Map A complete functional code map is produced. Full documentation of processes, dependency, and data flow. The system is now fully legible. | Phase 04 Transition With a fully characterized system, the organization chooses its path: migrate to a new platform, convert the code, or continue operations with superior and trainable material. |
| The outcome: a system your organization fully understands, owns, and can act on. | |||
The fourth phase is objectively the most exciting, but without the first three the path to success is unreliable. With a fully characterized system, migration and code conversion become realistic options for a more modern system. AI translation tools become genuinely powerful when you can run a translated version in parallel, validate its output against a documented baseline, and promote it with confidence. Or you may find that the right answer is neither migration nor conversion. For some organizations, a fully documented system that a less specialized team can operate without deep COBOL expertise may be the most valuable outcome available. It preserves continuity, eliminates single-point-of-failure dependency, and creates the breathing room for a deliberate, phased, risk-reduced modernization strategy.
The market reaction to Anthropic’s tool was not entirely wrong. AI-assisted translation is a meaningful development. It will matter. But it will matter most to the organizations that have already done the hard work to hand a fully characterized system to a translation tool and validate the output within a tightly controlled system for evaluation.
| Download the SalesE Legacy Intelligence white paper A practical guide to characterizing, validating, and mapping COBOL-dependent systems and building a clear path forward to efficiency and automation. Visit SalesE to download the white paper |










