Controller, Accounting, Financial Reporting

Ossium’s mission is to improve the health, vitality, and longevity of human beings through bioengineering. We develop, manufacture, and bank cell therapy products that apply the power of stem cell science to revolutionize treatment for patients with blood, immune, and orthopedic diseases. At Ossium, we empower our employees, maintain the highest standards of operational excellence, and are a force for good.

We are hiring a Controller to lead and strengthen Ossium’s accounting function as we scale. Reporting to our VP, Finance, you’ll lead a small team to start and own our accounting function so that our financial reporting keeps pace with our operations.

This role centers on raising the quality, speed, and reliability of our accounting operations. Responsibilities include leading the month-end close and preparing monthly flux analyses. You'll drive the annual financial statement audit under AICPA standards, managing the auditor relationship and working closely with our technical accounting team on complex areas such as revenue recognition, stock-based compensation, and new transactions. The role also involves strengthening our internal control environment, refining policies and procedures, and supporting accounting for R&D and clinical expense accruals, government grant/contract funding, and equity.

Finally, you'll partner with the VP, Finance on budgeting and forecasting and prepare clear written analyses and memos for auditors, leadership, and investors.

Our ideal candidate is a hands‑on leader who enjoys both rolling up their sleeves and setting direction. You’re detail-obsessed, energized by improving processes and systems, comfortable coaching a small team, and confident communicating with internal partners and external stakeholders alike.

• 10+ years of progressive accounting experience, including 3+ years in public accounting and 3+ years in a Controller/Assistant Controller role
• 3+ years of direct people management; hiring, coaching, and developing staff
• Proven track record of owning the full month-end, quarter-end, and year-end close process, including preparing financial statements and flux/variance analyses
• Experience leading financial statement audits end to end; preparing audit schedules, managing PBC requests, and serving as the primary point of contact
• Strong technical knowledge of US GAAP; the ability to research accounting issues and prepare technical memos
• Experience with inventory and cost accounting
• Hands‑on experience with Netsuite and
• Proven ability to work cross‑functionally with internal teams
• Advanced Excel and analytical skills
• Excellent verbal and written communication, including the ability to explain financial results clearly to non‑finance stakeholders
• This position is based in our San Francisco office; we maintain a hybrid schedule of Monday through Thursday in the office, with Friday as a remote work day

• Experience in a biotech, pharmaceutical, or FDA-regulated life sciences company
• Experience with cost accounting in a manufacturing, GMP, or lab‑processing environment, including standard costing and inventory valuation for biological or perishable products
• Implementation of an inventory module/integration of an inventory management system with Net Suite
• Experience with clinical trial/R&D expense accruals, including CRO & CDMO arrangements
• Experience accounting for government grants or contracts

• Lead, mentor, and develop the accounting team; set priorities/review work; help plan future growth
• Oversee all corporate accounting functions, including AP/AR, revenue, payroll accounting, fixed assets, and financial reporting
• Own the monthly, quarterly, and year‑end close; prepare financial statements…