Assistant Controller

Thinking Machines Lab's mission is to empower humanity through advancing collaborative general intelligence. We're building a future where everyone has access to the knowledge and tools to make AI work for their unique needs and goals. We are scientists, engineers, and builders who’ve created some of the most widely used AI products, including ChatGPT and Character.ai, open-weights models like Mistral, as well as popular open source projects like PyTorch, OpenAI Gym, Fairseq, and Segment Anything. About the Role Thinking Machines Lab is hiring an Assistant Controller to own our core accounting function and financial operations through a period of exceptional growth. Reporting to the Controller, you will lead month-end close, financial reporting, internal controls, audit readiness, and accounting policy - and build the infrastructure that a company operating at the frontier of AI demands. This is a senior, high-judgment role that pairs strategic leadership with hands-on execution. You will partner with cross-functional leaders and key external advisors, build and lead a high-performing accounting team, manage critical service-provider relationships, and serve as a financial linchpin for the organization. The right person operates decisively amid ambiguity, moves quickly without compromising rigor, and is motivated to help define what world-class finance looks like at a company shaping the future of technology. What You'll Do Own core general-ledger accounting across the balance sheet, operating expenses, international entities, and intercompany activity, ensuring accuracy from the transaction level through to a clean monthly close. Lead the month-end and quarter-end close, setting the standard for timeliness and quality and driving the process improvements that sustain it at scale. Own the accuracy, completeness, and timely delivery of all financial reporting. Design, document, and implement scalable end-to-end accounting processes—close, accounts payable, payroll, procurement, and indirect tax—building them where they don't yet exist and re-engineering them as the company grows. Architect and maintain the company's internal control framework, and lead audit readiness end to end. Own the accounts payable and procure-to-pay function, including vendor onboarding, purchase-order issuance, two-way matching, expense management, and payment runs, with the controls and automation to scale it. Own multi-state payroll processing in Rippling—ensuring accurate, compliant, and timely pay runs, tax withholding, and filings—and own the integrity of the payroll-to-GL flow in partnership with People Ops. Own indirect tax compliance across US sales-and-use tax and international VAT/GST, including nexus and registration analysis, taxability and exemption determinations, filings, and the tax-automation tooling that supports them as the company expands across jurisdictions. Lead cash management operations, including daily cash positioning, bank account administration, payment controls, and cash-flow forecasting in partnership with Finance. Own relationships with external auditors, outsourced accounting partners, and technical accounting advisors, holding each to a high bar. Bring sound accounting and risk judgment to new research and product initiatives from the outset, partnering cross-functionally to build scalable processes. Lead system implementations and automation—including AI-assisted tooling—to build an accounting function that scales without scaling headcount linearly. Partner with Finance, Tax, Legal, and Operations to translate financial performance into recommendations that inform senior-leadership decisions. Recruit, mentor, and develop a high-performing accounting team, and build the organizational capacity to support rapid scale. Skills and Qualifications Minimum qualifications: CPA or CA with deep expertise in US GAAP and technical financial reporting. Bachelor's degree in Accounting, Finance, or a related discipline. 15+ years of