About us PhysicsX is a deep-tech company with roots in numerical physics and Formula One, dedicated to accelerating hardware innovation at the speed of software. We are building an AI-driven simulation software stack for engineering and manufacturing across advanced industries. By enabling high-fidelity, multi-physics simulation through AI inference across the entire engineering lifecycle, PhysicsX unlocks new levels of optimization and automation in design, manufacturing, and operations — empowering engineers to push the boundaries of possibility. Our customers include leading innovators in Aerospace & Defense, Materials, Energy, Semiconductors, and Automotive.
The Role We are looking for a Global Payroll Manager to join the PhysicsX Finance team. The immediate focus of this role will be to own and manage US payroll , including bi-weekly payroll processing, payroll compliance, payroll controls, reconciliations and coordination with our People team and external payroll providers. Over time, this role will expand to support and improve our global payroll processes and infrastructure , helping us build a consistent, controlled and scalable payroll operating model across all countries where PhysicsX operates. This is a hands-on role for someone who is comfortable operating in a fast-growth environment, enjoys improving processes, and understands that payroll is not just a back-office process — it is one of the most important employee experience and governance functions in the company. Key
Responsibilities US Payroll Ownership Own the end-to-end US payroll process, ensuring payroll is processed accurately, on time and in compliance with federal, state and local
requirements. Manage bi-weekly payroll cycles, including payroll inputs, changes, approvals, funding, checks and post-payroll reviews. Work closely with the People team to ensure payroll data is complete, accurate and properly authorised. Review payroll changes including new starters, leavers, salary changes, bonuses,
benefits deductions, tax adjustments and other variable pay items. Manage payroll compliance
requirements, including tax filings, year-end reporting, W-2s and other statutory obligations. Partner with
benefits providers to ensure employee deductions and employer contributions are correctly processed. Support payroll treatment of relocation, mobility, equity, taxable
benefits and other employee-related payments where required. Act as the main point of contact for US payroll queries, resolving issues quickly and professionally. Payroll Controls, Governance and Compliance Build and maintain a strong payroll control environment, including clear approval flows, segregation of duties and audit-ready documentation. Ensure People and Finance
responsibilities are clearly separated, with People owning HR master data and Finance owning payroll processing, review and release controls. Prepare payroll reconciliations, including payroll to GL, payroll funding, tax liabilities,
benefits deductions and employer costs. Support month-end close by ensuring payroll journals, accruals and reconciliations are accurate and submitted on time. Maintain clear audit trails for payroll changes, approvals and payments. Support internal and external audits by providing payroll documentation and responding to audit queries. Identify payroll risks and implement practical controls to reduce errors, delays and compliance exposure. Global Payroll Process Improvement Support the development of a global payroll operating model across the UK, US, Singapore and future jurisdictions. Help standardise payroll calendars, input templates, approval workflows, reconciliations and reporting across countries. Partner with local payroll providers to improve accuracy, timeliness and consistency of payroll delivery. Build scalable processes that can support significant headcount growth across multiple locations. Document payroll policies, procedures and controls so that the process is repeatable, transparent and resilient. Support future payroll system, HRIS and finance system improvements, ensuring payroll data flows are accurate and controlled. Help create global payroll reporting for Finance, People and leadership teams. Cross-functional Partnership Partner closely with People, Finance, Legal, Tax and external advisors to ensure payroll is accurate, compliant and aligned with business needs. Work with the Finance team to ensure payroll costs are correctly reflected in management accounts, budgets, forecasts and reporting. Support employee mobility and international expansion from a payroll perspective. Provide clear guidance to employees and internal stakeholders on payroll timelines, processes and
requirements. Bring a continuous improvement mindset to payroll and help build a payroll function that can scale with the company. What Success Looks Like In the first 3–6 months, you will have taken ownership of US payroll, built confidence in the payroll process, strengthened controls and created clear visibility over payroll inputs, approvals, reconciliations and deadlines. In the first 6–12 months, you will have improved the payroll operating model, reduced manual processes, strengthened audit readiness and helped create a more consistent global payroll framework. Longer term, you will help build the payroll infrastructure required to support a global, high-growth company operating across multiple jurisdictions. About You You are an experienced payroll professional who understands the importance of accuracy, confidentiality, compliance and employee trust. You are detail-oriented, organised and able to operate effectively in a fast-moving environment. You are comfortable being hands-on, but you also know how to step back and improve the underlying process. You can work through complexity, partner with multiple teams and build practical controls without slowing the business down unnecessarily.
Requirements Strong experience managing US payroll, ideally in a multi-state environment. Good understanding of US payroll tax,
benefits deductions, statutory reporting and year-end payroll
requirements. Experience working with external payroll providers and HRIS/payroll systems. Strong understanding of payroll controls, reconciliations and audit
requirements. Ability to work closely with People, Finance, Legal and external advisors. Excellent attention to detail and ability to manage deadlines in a recurring payroll cycle. Strong communication skills and ability to explain payroll matters clearly to non-payroll stakeholders. Comfortable working in a fast-growth, scaling company where processes are still being built and improved. High level of discretion and professionalism when handling confidential employee information.
Nice to Have Experience supporting payroll across multiple countries. Experience in a technology, engineering, SaaS or high-growth start-up environment. Experience with employee mobility, relocation, expatriate payroll or cross-border payroll matters. Experience supporting payroll accounting, payroll journals and month-end close. Experience improving payroll systems, workflows or automation. CPP or similar payroll qualification. Our delivery teams drive innovation to turn AI models into practical solutions - read our blog to learn more about how you’ll contribute to this exciting journey! What we offer Build what actually matters Help shape an AI-native engineering company at a formative stage, tackling problems that genuinely matter for industry and society. This is work with real-world impact - and something you can be proud to stand behind. Learn alongside exceptional people Work with a high-caliber, collaborative team of engineers, scientists, and operators who care deeply about doing great work, and about helping each other get better. We come from diverse backgrounds, but we share a commitment to operating at the highest level and addressing some of the most complex challenges out there. If you’re ambitious, thoughtful, and driven by impact, you’ll feel at home. Influence over hierarchy We operate with a flat structure: good ideas win - wherever they come from. Questioning assumptions and challenging the status quo isn’t just welcomed, it’s expected. Sustainable pace, long-term ambition Building meaningful technology is a marathon, not a sprint. We believe in balancing focused, ambitious work with a life beyond it. Our hybrid model blends time together in our New York office with work-from-home days, giving you the flexibility to work sustainably while staying connected in person. And it doesn’t stop there … 🚀 Equity options - share meaningfully in the company you’re helping to build. 💰 5% contribution to 401(k) - build long-term security with a strong retirement plan. 🍽️ Free team lunch 1x/week - good food, great company, and space to connect. 🏥 Private health insurance – comprehensive cover for you, offering total peace of mind. 👶 Enhanced parental leave – 3 months full pay paternity and 6 months full pay maternity leave, to provide extra flexibility during the moments that matter most. ☀️ 20 days of Annual Leave (+ Public Holidays) - because taking time to rest matters. 📈 Personal development – dedicated support for learning, development, and leveling up over time. 💪 Gympass / Wellhub (subsidized) – for you and up to 3 family members, supporting both physical and mental wellbeing. 💳 Flexible Spending Account (FSA) – set aside pre-tax dollars for eligible healthcare expenses. 🔎 Watch this space, we’re continuing to build this as we grow… Salary: $100,000 - $190,000 We value diversity and are committed to equal employment opportunity regardless of sex, race, religion, ethnicity, nationality, disability, age, sexual orientation or gender identity. We strongly encourage individuals from groups traditionally underrepresented in tech to apply. To help make a change, we sponsor bright women from disadvantaged backgrounds through their university degrees in science and mathematics. We collect diversity and inclusion data solely for the purpose of monitoring the effectiveness of our equal opportunities policies and ensuring compliance with UK employment and equality legislation. This information is confidential, used only in aggregate form, and will not influence the outcome of your application.
