Key Takeaways

  • Rillet’s Series C gives the AI-native ERP developer a $1 billion post-money valuation.
  • More than 600 customers now use Rillet, including Neuralink, Skild AI, Mercor, Postscript, and Windsurf.
  • Replacing established accounting systems will depend on auditability, security, integrations, and finance teams’ willingness to migrate.

Rillet has raised $100 million in a Series C led by ICONIQ, reaching a post-money valuation of $1 billion as it tries to replace accounting systems from NetSuite, SAP, Workday, Oracle Fusion, and Microsoft’s Great Plains.

Sequoia Capital, Andreessen Horowitz, Oak HC/FT, Bain Capital Ventures, Sequoia Global Equities, Battery Ventures, FirstMark, Scale Venture Partners, and Creandum also participated. The financing is Rillet’s third round in the past year and brings its total funding to more than $200 million since its public launch in 2024.

That pace reflects a broader shift inside corporate finance. Gartner found that 58% of finance functions used AI in 2024, up 21 percentage points from 2023, and predicted that 90% would deploy at least one AI-enabled technology by 2026. Gartner also placed generative AI in finance at the “peak of inflated expectations” in 2024, underscoring both investor enthusiasm and execution risk alongside Rillet’s rapid ascent.

Founded in 2021 by Nicolas Kopp and chief technical officer Stelios Modes, Rillet is headquartered in New York, with offices in San Francisco and Barcelona. Modes previously served as the US CEO of German neobank N26.

Kopp’s premise came from waiting weeks for business metrics while working as a bank executive. Instead of attaching AI features to a conventional ERP, Rillet states it rebuilt the general ledger around an “agent-first” architecture. Its AI agents can perform parallel tasks, shifting accountants from manual entry toward transaction review and exception handling.

Automating a general ledger carries strict operational requirements compared to generating management summaries. The ledger manages revenue recognition, reconciliations, close processes, reporting, and audit evidence. Any AI-led workflow therefore has to preserve approvals, explain how entries were produced, and allow human reviewers to trace changes.

Rillet’s customer growth suggests the proposition is gaining traction. The company reports more than 600 customers, including public companies, non-technology businesses, and AI developers such as Neuralink, Skild AI, and Mercor. According to published company data, its annual recurring revenue doubled every quarter following its previous financing and then doubled again during the three months before the Series C.

Customer examples underline the labor-efficiency pitch. Mercor, which is said to generate more than $2 billion in annual recurring revenue, operates with a three-person finance team using Rillet’s agents. Postscript closes its books in three days, while Windsurf has managed its finances with a two-person team.

Those examples are striking, but translating them to companies with decades of historical data, customized controls, multiple subsidiaries, and complicated regulatory obligations presents a harder test.

Rillet is not entering an empty market. Campfire positions itself as a modern alternative to NetSuite. Puzzle and Digits target simpler bookkeeping needs among smaller startups. Established finance-automation vendors, including Billtrust, HighRadius, and Basware, add another competitive layer.

Rillet is aiming higher up the complexity curve, targeting public companies and businesses with detailed revenue models. Partnerships with EY, KPMG, and RSM help address implementation, controls, and audit requirements that often shape enterprise ERP decisions.

Governance will matter just as much as product speed. The NIST AI Risk Management Framework offers a structure for identifying and managing AI-related risks, while ISO 27001 addresses information security controls relevant to financial data and ERP integrations. Buyers are likely to examine permissions, model oversight, data retention, change logs, and fallback procedures before allowing agents to post material transactions.

While the commercial opportunity in modernizing legacy accounting systems is substantial, finance departments tend to move cautiously when adopting new core systems. Rillet’s funding provides capital to build enterprise capabilities, but its primary operational goal is proving that a leaner finance team can remain controlled, auditable, and dependable as customer complexity rises.