Exclusive: Accounting AI startup Rillet reaches unicorn status with $1 billion valuation. Its founder says he wants to give CFOs back their weekends

Rillet went from launch to unicorn in about two years, and the speed of that climb says a lot about how eager investors are to bet against the old guard of enterprise finance software. The company just closed a $100 million Series C at a $1 billion valuation, led by ICONIQ, with Sequoia Capital, Andreessen Horowitz and Oak HC/FT returning alongside new backers including Bain Capital Ventures, Battery Ventures, FirstMark, Scale Venture Partners, Sequoia Global Equities and Creandum. It's the company's third raise in a year, pushing total funding past $200 million, and ICONIQ's Seth Pierrepont is taking a board seat.

Co-founder and CEO Nicolas Kopp frames the mission in personal terms. He has a finance and accounting background himself, and he says the goal is to stop CFOs from losing their weekends to spreadsheets and slide decks. Rillet isn't coming for accounting jobs, he insists — it's meant to be the tireless back office that lets finance professionals actually use their expertise instead of drowning in data entry.

The growth numbers back up the urgency. Rillet launched publicly around two years ago, landed a Sequoia-led Series A last summer, and closed a Series B just weeks after that. New annual recurring revenue doubled quarter over quarter around that Series B, and doubled again in the three months before this latest round. The company now counts more than 600 customers, including AI names like Neuralink, Skild AI and Mercor. Roughly 40% of its customer base now sits outside tech and AI entirely, in industries as unglamorous as waste recycling and as glossy as movie studios. Mercor's finance team, Kopp says, is running a business scaling past $2 billion in annual recurring revenue with a headcount of just three, using Rillet's AI agents to do it.

The pitch against legacy players — Oracle Fusion, SAP, Workday, Microsoft's Great Plains, NetSuite — is architectural, not just cosmetic. Those systems were built for humans to input and check numbers by hand. Rillet is built agent-first, running hundreds of operations in parallel and, Kopp argues, producing cleaner data with a full audit trail than manual processes ever could. Pierrepont echoes that in the funding announcement, pointing to customers running multibillion-dollar operations with finance teams a tenth the traditional size, closing their books continuously rather than in periodic scrambles.

Kopp credits much of the recent momentum to a sudden leap in the underlying AI models, saying things started "lighting on fire" in the last six months, with tasks that used to eat a full workday now taking minutes. That timing lines up conveniently with a separate problem the profession has been facing: fewer new graduates going into accounting. Kopp sees the shrinking talent pipeline as part of Rillet's opening, and the company has been building credibility with the establishment to match — an alliance with EY on AI-native finance transformation, and partnerships with more than half of the Accounting Today top 20 CPA firms. Its support team, staffed partly by people with accounting training, has reportedly shipped feature requests within two to three hours of a customer asking, something Kopp says wasn't possible even a year ago.