Did AI Just Kill COBOL?

Описание: When you tap your card, there's a good chance decades-old COBOL code is involved somewhere. This week OpenAI published results showing its latest models can now rewrite that code into modern languages almost perfectly, at least on its own tests. So should banks panic? Or should someone else?

We go through what OpenAI's tests really measured (like for like), the £2 ÷ 3 rounding problem that can quietly move money, why developers say proving the rewrite is the real bottleneck, what happened to IBM's shares, and why some think the consultancies are more exposed than the banks.

⏱️ Chapters
0:00 AI just learned COBOL
0:31 What is COBOL?
1:24 What OpenAI found
2:30 The catch: two pounds, three ways
3:18 Why it's harder than it looks
4:00 Who should worry?
4:43 The honest caveat
4:57 So, should banks panic?

📄 The source
• OpenAI, "Advancing coding in low-resource programming languages", 19 Oct 2026: https://openai.com/index/low-resource...
• MultiLangBench (the public database-building test): https://github.com/openai/MultiLangBench

📚 Other sources
• COBOL rounding rule (IBM Enterprise COBOL, ROUNDED phrase): https://www.ibm.com/docs/en/SS6SG3_6....
• TSB's 2018 platform switch: independent review (Slaughter and May, 2019) https://www.tsb.co.uk/news-releases/s... · FCA final notice https://www.fca.org.uk/news/press-rel... · 1.9m active digital users: TSB evidence to the Treasury Committee, May 2018 · £330.2m post-migration costs: TSB 2018 results
• Commonwealth Bank of Australia's core banking overhaul (iTnews, 2012): https://www.itnews.com.au/news/commba...
• IBM's 13% fall on 23 Feb 2026 (CNBC): https://www.cnbc.com/2026/02/23/ibm-i...
• IBM Q3 2026 earnings, 21 Oct: https://www.ibm.com/investor/events/e...
• OpenAI's Codex partners incl. Accenture, Infosys and TCS (21 Apr 2026): https://openai.com/index/scaling-code...
• Replies quoted on screen: https://x.com/Uncle_Joe_Gamer/status/... · https://x.com/pggalaviz/status/211232...

🔎 Accuracy notes
• Every score is from OpenAI's own tests. The COBOL migration test is not published; the database test (MultiLangBench) is.
• 5.4% → 86.6% compares both models at the same (low) reasoning setting, at about 39% lower cost. With more thinking time the older GPT-5.6 Sol reached 65.2% and GPT-6.1 Sol 97.9%.
• The 20-language database test compared GPT-6 Astra with GPT-5.6 Sol, both at maximum effort, and scores the average share of tests passed, so partial credit counts.
• GPT-5.6 Sol is two releases older than GPT-6.1 Sol (GPT-6 Sol came in between); OpenAI's COBOL chart shows GPT-6 Sol at 20.8% on the low setting.
• The 40%+ / 95% / 80% COBOL figures are IBM's, quoted by OpenAI (similar figures appeared in a 2017 Reuters graphic).
• The £2 ÷ 3 example, the test-run screens, the batch schedule, the "people who know COBOL" figure, the migration-job bar and the reconciliation ledger are illustrations. The IBM chart line is a stylised shape; the −13.15% is real.
• After OpenAI's post (published after the US close on 19 Oct), there was no sell-off: IBM and the big IT consultancies traded higher on 20 Oct, though the whole sector was up ahead of IBM's earnings.
• TSB's 2018 problems were a switch between banking platforms (from Lloyds' systems to Sabadell's Proteo4UK), not a COBOL rewrite. The review found the new platform "not ready at Go Live because it had not been sufficiently tested or proved". The £330.2m is gross, partly recovered from TSB's IT supplier.
• GPT-6.1 Sol launched on 29 Sep 2026; OpenAI's 19 Oct post reported new test results, not a new model.

🎬 Made with AI on one home computer: voice by Chatterbox Turbo (local), music by ACE-Step 1.5 (local), footage by LTX-2.5 (local). Sound effects: Pixabay. Edited with HyperFrames.

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