Member-only story
Your Bank’s COBOL Isn’t a Problem. It’s an Opportunity.
How AI agents are doing what 30 years of digital transformation couldn’t
Yanli Liu12 min read·Just now--
When I started my career in banking, one of the first things I learned was that nobody touches the mainframe. Not because it’s fragile. Because it works. It processes millions of transactions a day, it never goes down, and nobody fully understands how it does what it does anymore.
That last part is the problem.
Mainframes handle 83% of all global banking transactions. There are 220 billion lines of COBOL in active use, with 1.5 billion new lines written every year. The average COBOL programmer is 58 years old, and 10% are retiring each year. The Netherlands is already rehiring retired COBOL experts because critical knowledge has walked out the door.
Banks know they need to modernize. But 70–80% of attempts to replace these systems fail. Nordea burned through €1.65 billion trying to swap its core banking platform. Deutsche Bank’s Postbank migration locked customers out for weeks and triggered BaFin intervention. TSB’s botched migration hit 5.2 million customers and cost over £330 million.
The question has been wrong for 30 years: how do we replace the mainframe?
