Assistant Controller

ABOUT ARENA INTELLIGENCE Arena is the platform for evaluating how AI models perform in the real world. Founded by researchers from UC Berkeley's SkyLab, we're on a mission to measure and advance the frontier of AI for real-world use, and to build the foundation for everyone to understand, shape, and benefit from it. Tens of millions of people use Arena each month to evaluate how frontier systems handle the work they actually do. The preferences they share power the most transparent, rigorous, and human-centered evaluations in AI. Leading AI labs, enterprises, and independent researchers rely on our work and open datasets to understand how models behave in real workflows: agentic coding, creative generation, professional productivity, and beyond. We go beyond leaderboards and decompose what human experience reveals about AI, so models advance toward the work people actually do. We're a team of researchers, academics, builders, and creatives from UC Berkeley, Google, Stanford, and DeepMind. We seek truth, move fast, and value craftsmanship, curiosity, and impact over hierarchy. We're building a company where thoughtful, curious people from all backgrounds can do their best work together, in an office culture that radiates excellence, energy, and focus. About the Role As Assistant Controller, you'll build our accounting function from the ground up — the systems, controls, and infrastructure that support our next phase of growth. This is a rare opportunity to be the first dedicated accounting hire at a company whose customers include the world's top AI labs and enterprises, with a product that's become the industry standard for AI evaluation. Reporting to the Head of Finance, you'll lead all aspects of accounting: from managing day-to-day operations and owning the month-end close, to implementing core systems, standing up internal controls, and driving audit readiness. You'll work across complex enterprise contracts, own revenue recognition, and build the cost accounting framework for a fast-scaling business. You'll partner with an external accounting firm on day-to-day operations as you build out the function. You’ll - Own monthly, quarterly, and annual financial closes, delivering GAAP-compliant financial statements and analyses. - Manage day-to-day financial operations including AP/AR, expense allocations, balance sheet reconciliations, and invoice reconciliation across major enterprise accounts. - Own revenue recognition end-to-end, applying ASC 606 across complex enterprise contracts - Design and implement scalable financial systems, processes, and controls to support rapid growth, including leading our first ERP implementation. - Manage cash flow and working capital timing across large enterprise billing cycles. - Build and maintain a strong internal control environment and establish accounting policies from scratch. - Lead audit and tax readiness — serve as the primary liaison for external auditors and ensure compliance with all local, state, and federal tax requirements. - Partner with the Head of Finance and leadership to translate data into strategic insights and define the roadmap for building out the accounting function as the company scales. You’ll Have - 8+ years of progressive experience in accounting, with a strong track record at high-growth technology startups. Big 4 foundation preferred. - Deep expertise in U.S. GAAP, specifically revenue recognition (ASC 606), stock-based compensation, and consolidations. - Practical experience leading a company through its first financial statement audit and building internal controls from scratch. - Strong background in implementing and managing ERP systems and modern finance tools (e.g., Ramp). - CPA certification and strong technical accounting foundation required. - A builder mindset: hands-on, resourceful, and comfortable owning both the details and the architecture of the function. - Actively leveraging AI in your workflows today — it's already part of how you work, not