Accounting AI startup Rillet has closed a $100 million Series C at a $1 billion valuation, making the Rillet Series C unicorn milestone one of the faster rises in enterprise software, reached just years after the company was founded.
The round was led by ICONIQ, with returning backers Sequoia Capital, Andreessen Horowitz and Oak HC/FT joining new investors including Bain Capital Ventures, Battery Ventures, FirstMark, Scale Venture Partners and Creandum. ICONIQ general partner Seth Pierrepont is joining the board.
Total funding now exceeds $200 million, making this Rillet’s third fundraise in the past year.
Rillet Series C: what the money reflects
Co-founders Nicolas Kopp and Stelios Modes started the company in 2021, according to The Next Web. Kopp launched the platform publicly roughly two years ago, raised a Series A led by Sequoia last summer, then closed a Series B weeks later.
The company says new annual recurring revenue doubled quarter over quarter after the Series B, then doubled again in the three months before this latest raise.
Rillet now serves more than 600 customers, including Neuralink, Skild AI and Mercor. Agent activity across those customers is growing about 70% month on month, The Next Web reported.
Roughly 40% of the customer base sits outside the tech and AI sectors, Kopp said, spanning industries including waste recycling and film production.
Mercor has become the company’s headline reference customer. According to Rillet, Mercor’s finance team uses its AI agents to manage a business scaling past $2 billion in annual recurring revenue with a headcount of just three.
‘Rillet is the clear leader in AI-native accounting infrastructure,’ Pierrepont said in a statement. ‘What stands out is how customers actually run on it, multibillion-dollar businesses operating with finance teams a tenth the traditional size, closing their books continuously.’
Taking aim at Oracle, SAP and legacy ERP
Rillet’s pitch targets enterprise resource planning incumbents directly. Kopp named Oracle Fusion, SAP, Workday, Microsoft’s Great Plains and NetSuite as systems built for a pre-AI era.
‘Some of these giants that seemed untouchable’ are now facing serious disruption, Kopp said.
The architectural argument is central to that claim. Traditional ERP systems were designed for humans to input and review data, Kopp said, leaving finance chiefs ‘dragged down into the day-to-day minutiae of numbers.’ Rillet is built agent-first, with AI systems capable of running hundreds of operations in parallel.
That, Kopp argues, produces cleaner financial data and a complete audit trail. ‘Proving out the work layer is mission-critical for enterprise readiness,’ he said.
Rillet has also moved to build credibility within the accounting establishment. Earlier this year, the company launched an alliance with EY for AI-native finance transformation. It says it now partners with more than half of the Accounting Today top 20 CPA firms.
Kopp traced much of the company’s recent momentum to rapid improvements in underlying AI models. ‘Especially in the last six months, things started lighting on fire in a good way,’ he said, describing tasks that once took a human a full day now taking a couple of minutes.
For Kopp, the question is not job replacement. CFOs ‘can’t see their families on weekends,’ he said, because of time spent reviewing data and building presentations. ‘Our message is not that we’re coming after jobs. That’s just not correct,’ he said. ‘We’re positioning AI as a helper to that individual and what they can achieve.’
The company also points to a separate structural pressure: fewer graduates are entering accounting careers. Kopp sees the talent shortfall as part of the long-term opportunity for AI-native platforms like Rillet to fill the gap as business complexity continues to grow.
Rillet’s product development has accelerated alongside its AI capabilities. Kopp said customer support staff, many with accounting training, have shipped feature requests within two to three hours of a customer raising them. ‘That wasn’t possible six to 12 months ago,’ he said.
