Our Finance as a Service (FaaS) offering provides high-growth and emerging companies with an integrated finance function that combines experienced professionals, deep industry experience, AI-enabled technology, and disciplined processes. FaaS brings together strategic finance leadership, accounting operations, and transaction processing, helping organizations scale efficiently without prematurely building a full internal finance team. Whether launching a new entity, strengthening financial operations, or supporting continued growth, our team works alongside yours to provide reliable execution, experienced financial oversight, and actionable insight.
Strategic Finance Leadership
Strategic Finance Leadership
Access experienced finance leadership to improve financial visibility, support informed decision-making, and help your finance function evolve with your business. Our executive-level support is tailored to your company’s needs and stage of growth.
- CFO and VP Finance-level support
- Cash runway and financial planning
- Budgeting and forecasting management
- Management, board and investor reporting
- KPI development and performance insights
Controller & Accounting Operations
Controller & Accounting Operations
Build a disciplined accounting foundation through controller-level oversight, standardized workflows, and day-to-day accounting operations designed for accuracy, consistency, and scalability.
- Embedded finance systems expertise to optimize workflows, automation, and technology
- General ledger management
- Month-end close management
- Account reconciliations
- Financial reporting
- Audit Readiness and compliance support
Finance Operations
Finance Operations
Standardized, technology-enabled finance operations that keep day-to-day processes moving efficiently, consistently, and with appropriate oversight.
- Procure-to-pay administration
- Payroll administration
- Employee expense management
- Transaction processing
- Standardized finance workflows
- Cap table and options administration support
FEATURED CASE STUDIES
-
A clinical-stage, venture-backed biotechnology company was preparing for an IPO on an accelerated timeline. The company’s finance leader, whose background was in FP&A, had no accounting team in place and needed experienced operational accounting and reporting support.
-
A newly formed biotechnology company needed to build its accounting and finance function to help secure, and then support, its first financing – a significant VC-led Series A.
Let’s build your modern finance function
Talk with our team about your finance operations, reporting needs, technology environment, and plans for growth.
Schedule a Call
Marcello Castellano
Partner – Finance as a Service
Marcello brings over 20 years of accounting advisory and consulting experience to WilliamsMarston.
For the last several years, he has focused exclusively on the life sciences sector, partnering with early-stage biotechnology companies to navigate the complex journey from initial formation through successful initial public offerings. He is focused on supporting operational accounting and strategic finance, providing leadership that bridges the gap between technical compliance and long-term business strategy.
Prior to this, Marcello spent several years as a consultant and advisor supporting Private Equity portfolio companies, where he led finance effectiveness initiatives to optimize reporting, processes, and scalability. His career began at PwC, where he rose to the level of Director. During his tenure at PwC, he gained extensive international and capital markets experience within the Global Capital Markets group in Europe and the Transaction Advisory practice, where he focused on supporting Private Equity buy-side due diligence.
Marcello’s unique background combines Big Four technical rigor with hands-on operational expertise. By combining technical expertise with a pragmatic operational lens, Marcello empowers leadership teams to build scalable finance organizations that support the unique needs of evolving biotech and technology firms.