Accounting AI startup Rillet secures $100 million Series C, reaches $1 billion unicorn status

Rillet, a two-year-old startup that describes itself as the first truly AI-native accounting platform, closed a $100 million Series C that lifts its valuation to $1 billion, joining the latest wave of AI-driven unicorns. The financing was headed by ICONIQ and included existing backers Sequoia Capital, Andreessen Horowitz and Oak HC/FT, alongside new investors such as Bain Capital Ventures, Battery Ventures and Creandum, and resulted in ICONIQ general partner Seth Pierrepont joining the board.

Founder and CEO Nicolas Kopp framed the milestone as a means to free chief financial officers from endless spreadsheet work, emphasizing that AI will act as a tireless back-office rather than replace accountants. Rillet now counts over 600 customers, ranging from AI leaders like Neuralink and Skild AI to firms in waste recycling and film production, with roughly 40 % outside the tech sector. Its flagship client Mercor uses Rillet’s AI agents to manage a finance operation supporting more than $2 billion in annual recurring revenue with just three staff.

The company argues its agent-first architecture outperforms legacy ERP suites such as Oracle Fusion, SAP and Workday by automating manual accounting tasks, delivering cleaner data and a full audit trail. Recent alliances with EY and partnerships with many top CPA firms aim to cement its credibility as it pushes enterprises to replace traditional systems with its AI-centric solution.