Hryhorii Tatsyi, CTO of Raiffeisen Bank Ukraine (~900 IT engineers), published a 12-month longitudinal account (May 2025 → April 2026) of his organization's AI transformation on Medium in May 2026. The title crystallizes the thesis: "AI didn't make our engineers just faster. It made them different." This is one of the rare quantified organizational case studies from a regulated European bank available in 2026.

Core data: IT headcount contracted by 75 people (−8%, including 64 engineers) — yet more code shipped, fewer incidents, improved security. AI adoption rose from 62% to 83%; 68% of engineers receive ≥50% of their code via AI assistance; new-engineer onboarding 60-90 days → ~40 days (consistent with Anthropic data of 82→40 days, an independent convergence).

Three emerging archetypes: (1) Copilot-only: +10-25% on PRs, stable scope; (2) Multi-tool: story points ×1.5-3, cross-repo scope +50-80%; (3) Claude on corporate stack: code volume ×4.5, radically expanded scope. Counterintuitive insight: "AI lifts underperformers to baseline" rather than mainly accelerating top performers — the distribution tightens from the bottom. Senior architects return to active development after years away from it.

Seven new AI products (that did not exist before): Service Knowledge Hub (57 microservices, 83 releases/month), Mobile Android workflow CI, AI Agent Portal (2,085 users / 649 MAU in 87 days, MCP generation via OpenAPI), Shift-left Security Plugin (−82% exposed secrets), DevPortal Backstage + Kubernetes diagnostics agents (−68% critical incident resolution time), DRAIF MCP text-to-SQL Data Lake with 10,000 tables (embedding fine-tuned ×2 OpenAI), Call Evaluation (>97% accuracy, voted best product in the Raiffeisen Bank International group). Stability: blocking incidents −70%, critical resolution −68%, high-severity security alerts resolved +155%.

Strategic pivot thesis: "AI expanded our production possibility frontier, and we deliberately allocated the freed capacity" — toward features, stability, and technical-debt repayment. Reframed evaluation question: not "by how much % did existing KPIs increase" but "what did your engineers build that didn't exist before".

Tie-in to the watch corpus: numeric convergence around the committed median with Frizzo (2026-05-05), Wescale (2026-05-03), Curran/Intercom (2026-04-16), DORA 2025, Stanford Denisov-Blanch (2025-11-23). Independent convergence on ~40-day onboarding with Anthropic. Productive tension with Cherny / Curran top 5% / Karpathy (elite 10×+ tail): the distribution tightens from the bottom AND widens at the top — both readings coexist. Cross-cutting convergence on "the job is changing shape" with Frizzo, Karpathy, Mornati, Habert. To be used for banking/regulated-sector executive committees, transformation sponsors, and the productivity-distribution-equity debate.