Returnzero, a Korean voice AI startup, has successfully raised approximately USD 3.7 million(KRW 5 billion) in Series C funding. The investment round was led by Woori Venture Partners and Shinhan Venture Investment. Returnzero plans to allocate the secured capital toward advancing its AI voice technology, acquiring key talent, expanding services, and entering global markets.

Returnzero’s core competitive advantage lies in its Proactive Voice Agent (PVA) technology. This technology leverages high-performance speech-to-text (STT) capabilities to accurately analyze and convert human speech into text, then combines conversational AI based on natural language understanding to enable context comprehension and question-answering, achieving near-human interaction. Notably, the company’s proprietary speech recognition engine, trained on over 15 million hours of Korean voice data, delivers industry-leading accuracy and has demonstrated stable performance even in noisy environments.

Returnzero currently operates Callabo, a large-scale automated meeting summarization service. Callabo automatically records all meetings and summarizes 30 minutes of content in just 30 seconds, dramatically improving work efficiency. Additionally, the service has obtained ISO 27001 international information security certification, establishing enterprise-grade security infrastructure, while strengthening personal data protection through voice data encryption and de-identification technologies.

Jung Juyoung, CTO of Returnzero, stated, “As Returnzero’s PVA technology holds a leading position in the domestic market, we will continue to invest heavily in its advancement to establish it as the standard for voice AI services. We also plan to evolve Callabo beyond a simple knowledge management tool into a conversational intelligence platform that will fundamentally innovate corporate communication methods.”

Choi Hyungseok, Team Leader at Woori Venture Partners, which led the investment round, commented, “We are confident that Returnzero, which has been driving innovation in Korea’s voice AI sector, will open up the next-generation conversational voice agent market. This investment is expected to accelerate the company’s global market entry.” Kim Jiwon, Deputy Manager at Shinhan Venture Investment, which co-led the investment, added, “Returnzero will set new standards in the Voice Agent field through its voice big data and AI technological capabilities.”

Lee Chamsol, CEO of Returnzero, emphasized, “Based on the trust of our investors, we will create services that can compete on the global stage, going beyond being Korea’s leading voice technology company. Through AI voice agents, we will fundamentally innovate corporate communication methods and maximize work productivity, growing into a company that leads the AI transformation of all enterprises.”

Meanwhile, Returnzero is a domestic voice AI company co-founded in 2018 by KAIST-graduate developers. The company has pioneered Korea’s voice recognition AI service market by launching VITO, an app that converts phone conversations to text, and Callabo, an enterprise AI meeting platform. Currently, Returnzero’s technology is being utilized across various sectors including finance, public services, and firefighting.