Upstage, the Korean AI startup behind the Solar large language model and Document Parse platform, has closed the first tranche of its Series C round at approximately $125.9M (KRW 180 billion), crossing the $1 billion valuation threshold to become the first generative AI company in Korea to achieve unicorn status.

The round was led by Sazze Partners, a Silicon Valley-based global venture capital firm that has backed Upstage since its earliest stages and has participated in every subsequent round. The firm’s continued lead role underscores its conviction in Upstage’s technical capabilities and sustained revenue growth.

Returning institutional investors Premier Partners, Shinhan Venture Investment, Mirae Asset Venture Investment, KB Securities, and InterVest also participated in the round. New investors include global fund Axiom Asia, along with Hyundai Motor Company and Kia Corp., Woori Venture Partners, and IBK(Industrial Bank of Korea).

Upstage has built its growth around two flagship products: Solar, its proprietary large language model (LLM), and Document Parse, an AI-powered document processing solution. The company has delivered revenue growth exceeding 130% year-over-year and was selected as the lead organization for the Ministry of Science and ICT’s Independent Foundation Model project — a government initiative to develop Korea’s own sovereign AI foundation model — cementing its standing as a nationally recognized AI developer.

With this closing, Upstage’s total cumulative funding reaches approximately $279.7M (KRW 400 billion). Since its founding in 2020, the company has raised at every stage: a seed round, followed by a $22.1M (KRW 31.6 billion) Series A in 2021, a $69.9M (KRW 100 billion) Series B in 2024, and a $43.4M (KRW 62 billion) Series B bridge round in 2025.

The fresh capital will be deployed toward expanding GPU infrastructure to support the Independent Foundation Model project and further LLM development, recruiting top AI talent domestically and internationally, and accelerating go-to-market efforts in the United States and Japan.

“This investment goes beyond simply raising capital — it reflects the market’s confidence in the journey Upstage has taken and the results we’ve delivered as Korea’s leading AI developer,” said Sunghun Kim, CEO of Upstage, in a statement. “We will continue to build world-competitive AI models that prove their worth not just in valuation, but in revenue — starting in Korea and extending across global markets.”