There is a specific sound every founder eventually learns to respect. Phones ringing. Customers waiting. Silence stretching just long enough to feel expensive. PolyAI was built inside that moment. Born from the University of Cambridge Dialog Systems Group in Nov 2017, Nikola Mrkšić, Tsung-Hsien Wen, and Pei-Hao Su were not chasing louder chatbots. They were chasing understanding, across accents, industries, and the messy reality of human speech.
That obsession just converted into scale. On Dec 15, 2025, PolyAI closed an $86M Series D co-led by Georgian, Hedosophia, and Khosla Ventures, with backing from NVentures, the British Business Bank, Citi Ventures, Squarepoint Ventures, Sands Capital, Zendesk Ventures, and Point72 Ventures. Valuation lands around $750M, up from $500M in May 2024. Growth without theatrics. Math without fantasy.
Nikola Mrkšić brings the scars and signal from VocalIQ and Apple Siri. Tsung-Hsien Wen brings Google-grade depth in dialogue systems. Pei-Hao Su brings research rigor shaped at Facebook AI Research. Together they built a voice first enterprise platform now running 2,000+ live deployments, spanning 45 languages across 25+ countries, serving 100+ enterprise customers. Roughly 70% of revenue comes from the US, and that number keeps leaning forward.
The technology stays disciplined. Agent Studio, launched April 2025, is designed for control, transparency, and production reality, not demo theater. PolyAI’s proprietary Owl ASR model posts a 0.122 word error rate on phone audio, the environment where most systems politely fail. Real-time streaming, multi-turn context, authentication, bookings, payments, all executed without uncanny valley drama.
The outcomes tell the story without shouting. At Landry’s Golden Nugget Hotels and Casinos, PolyAI contained 87% of calls on day one. Across customers, containment averages near 70% on interactions lasting about two minutes. A Forrester Total Economic Impact study shows a 391% ROI and $10.3M in average savings. Across the platform, PolyAI agents create roughly $1B in annual value by quietly doing the work of thousands.
There is a reason the British Business Bank committed £15M and why PolyAI now employs nearly 300 people across London, New York, San Francisco, Belgrade, Canada, and the Philippines. This is not about replacing humans. It is about letting enterprises breathe while customers feel heard. Voice is chaotic. PolyAI leaned into the noise, taught machines to listen, and turned customer service into something closer to a conversation than a queue.
Startups Startup Funding Venture Capital Series D AI AI Agents Voice AI Conversational AI Customer Support Enterprise Enterprise Tech Enterprise AI SaaS Technology Innovation Tech Ecosystem Startup Ecosystem
