Rillet, a San Francisco-based startup founded in 2024, has reached a $1 billion valuation in roughly two years, securing $100 million in a Series C round that came together in less than 48 hours. This latest funding, which brings the company’s total raised to over $200 million across three rounds in just 14 months, highlights the intense appetite for infrastructure capable of displacing legacy SaaS giants like NetSuite, Oracle Fusion, and SAP. As reported by TechCrunch, the speed of this capital injection-completed without the company even intending to hit the market-underscores a shift in investor focus from incremental software improvements to total architectural overhauls.
Most enterprise AI efforts today focus on augmentation, essentially bolting chatbots onto existing workflows to summarize emails or draft responses. Rillet is taking a different, more structural path. CEO Nicolas Kopp argues that “agents need more than access to data; they need to work inside the general ledger.” This is the company’s core thesis: AI agents should not be peripheral tools sitting on top of the finance stack; they should be the stack itself.
The company’s AI agent, Aura, operates directly inside the real-time general ledger. This approach aims to change the fundamental architecture of corporate finance by moving toward a continuous or “zero-day” close, potentially rendering the traditional, labor-intensive month-end process obsolete. While legacy vendors are busy adding AI features to their existing platforms, Rillet is positioning itself as a full-stack replacement. Seth Pierrepont, a General Partner at ICONIQ who joined the Rillet board, notes that “the general ledger could become more than a system of record and instead the operating system for finance.”
Building a new ERP is a massive technical challenge, but the real hurdle is trust. Rillet has secured a significant distribution advantage through alliances with major firms, including an EY alliance announced in April 2026. With KPMG and RSM also reported as partners, the company claims to work with more than half of the Accounting Today Top 20 CPA firms. This institutional backing provides a level of credibility that is often the biggest barrier for any startup attempting to displace entrenched incumbents.
The company’s growth is already visible, with over 600 customers including Neuralink, Skild AI, and Temporal. These organizations prioritize high-velocity, AI-native workflows, and for them, a 4-week implementation time for Rillet is a massive improvement over the 6-to-12-month slog typically required to deploy legacy ERPs. However, replacing a general ledger is not like swapping out a project management tool; it is the heart of a company’s financial truth. The migration difficulty is significant, and the risk of overvaluation in a market that moves this quickly is a practical caveat that finance leaders must weigh.
Rillet is part of a broader shift toward agent-as-a-worker (AaW) models. Just as HappyRobot has begun to automate vertical customer support and Twin1 AI focuses on worker replication, Rillet is applying the same logic to the finance department. By leveraging durable execution models-similar to the infrastructure provided by Temporal-Rillet is moving toward a world where the finance function is managed by agents that do not just report on the past, but actively execute the present.
The rapid adoption of Rillet by over 600 customers, combined with the increasing integration of agent-native ledgers by major accounting firms, suggests that the traditional, passive ERP model is facing a structural challenge that finance leaders must now evaluate. Whether Rillet becomes the new standard or simply forces legacy vendors to accelerate their own internal transformations is the next phase of this story. Finance leaders should watch how these Big Four partnerships evolve; if the auditors start mandating agent-native ledgers, the shift will be difficult to ignore.