Marsh McLennan Built Its Own AI for 90,000 People — at 1% the Cost

What happens when a global company with 90,000 employees decides not to buy enterprise AI — and builds it instead? That's exactly what Marsh McLennan did. They created LenAI, a purpose-built generative AI platform that runs entirely inside their own infrastructure, and they delivered it at roughly 1% of what a Microsoft Copilot rollout would have cost. The results are striking: early adopters are saving eight hours a week. The tool processes two million AI requests per month. And this isn't just a pilot — it's become core infrastructure for how the company operates. But the real lesson here isn't about building your own AI. It's about why purpose-built tools consistently outperform generic ones — and what that means for HR leaders making AI decisions today. In this episode, we break down how LenAI works, why Marsh McLennan's approach succeeded, and what the same principle looks like applied to hiring — where purpose-built AI like OVI is giving HR teams the same edge without requiring a single internal engineer.