AI-native accounting startup Rillet has crossed a major milestone after securing $100 million in fresh funding at a $1 billion valuation, becoming a unicorn in just 48 hours. Co-founder and CEO Nicholas Koop said the company was not actively fundraising when investor interest accelerated.
Founded out of stealth two years ago, Rillet has now raised $200 million in total from major backers including ICONIQ, Andreessen Horowitz, and Sequoia. The platform serves 600 customers, many of them moving away from legacy systems such as Oracle, NetSuite, Intuit, Sage Intacct, SAP, Workday, and Microsoft products.
The company's momentum has been fueled by strong adoption across businesses of different sizes, from laundromats to the NFL Hall of Fame. Koop said Rillet is designed for AI agents first, while still keeping humans in the loop for oversight and decision-making.
Rillet also emphasizes data protection and control. Its system routes requests to models such as OpenAI or Anthropic, while preventing customer data from being used to train those models. The platform also avoids cross-training between clients, keeping each dataset separate and proprietary.
In recent months, Rillet introduced a governance layer that lets accountants review how each AI action was made, including the numbers used and the calculations behind them. Koop said this kind of transparency has become more important as AI agents take on longer, multi-step workflows.
Investors say the company's rapid rise reflects a broader shift in finance software, where AI tools are beginning to reshape how accounting teams work. Koop believes the technology will support professionals rather than replace them, especially as routine tasks become more automated and advisory work grows in importance.
As AI-native finance tools mature, they may help define a more adaptive, data-driven future for accounting and business operations.
