Rillet hits unicorn status after $100 million raise in 48 hours

US-based artificial intelligence accounting startup Rillet has raised $100 million in a Series C funding round led by Iconiq, valuing the company at $1 billion. The investment was finalised within 48 hours of a board meeting where the company presented strong growth metrics, effectively securing unicorn status without a formal fundraising campaign.

According to the company, its annualised revenue rate doubled in the previous quarter alone. Rillet, which emerged from stealth two years ago, has now raised a total of $200 million from investors including Sequoia and Andreessen Horowitz. The rapid closure of the deal was attributed to the company’s demonstrated ability to displace legacy systems, with Iconiq general partner Seth Pierrepont noting that Rillet had already proven it could win against incumbents that have owned the category for decades.

The startup has acquired 600 customers, many of whom are replacing established accounting and enterprise resource planning software. Approximately 50 per cent of Rillet’s customers migrated from Intuit, while 30 per cent came from NetSuite and Sage Intacct, and 20 per cent from products by Oracle, SAP, Workday, and Microsoft. The company has also secured an alliance with EY to introduce AI tools to the auditing firm.

Rillet’s platform is designed for AI agents rather than humans, allowing accountants to work alongside automated systems for corporate bookkeeping. To address security and transparency concerns, the company released a governance feature three months ago that allows accountants to audit every decision made by the AI agents, including data sourcing and calculation methods. This feature was developed to compress agent data into a format understandable by humans, a capability Koop said became feasible only as AI agents grew more powerful.

The funding comes against a backdrop of a shortage of accountants in the United States, with the number of graduates in accounting degrees declining since at least 2010. The Bureau of Labor Statistics projects that accounting-related needs will grow by at least 5 per cent, adding 72,800 jobs by 2034. While current regulations for public companies require human approval for every transaction made by an AI agent, Rillet’s CEO Nicholas Koop believes these rules will evolve to align with the technology’s capabilities.

Iconiq’s Seth Pierrepont has joined the Rillet board following the investment, while Sequoia’s Julien Bek described the re-investment as an easy decision given the company’s growth. Bek noted that while Rillet’s initial focus is accounting, the company is reinventing the entire finance function, with agentic finance potentially becoming one of the largest application software opportunities of the AI era.