Interim Chief Financial Officer

Siena Partnership; Greater London; On-site; GBP 120,000 - 180,000; Part time

Job summary

Siena Partnership is seeking a proven interim CFO for a private equity-backed platform, to lead the first 100 days post-acquisition and professionalise the finance function.

The role focuses on delivering rapid diagnostics, establishing robust financial infrastructure, and enabling growth through enhanced reporting and governance within a sponsor-backed environment.

Qualifications

• Proven interim CFO with PE-backed business experience.
• Experience delivering post-acquisition finance transformations.
• Ability to establish PE-quality reporting and governance.

Responsibilities

• Lead post-acquisition 100-day finance workstream and execution plan.
• Establish confidence in revenue, margin, cash and working capital.
• Create PE-quality board reporting, dashboards and forecasting.
• Professionalise finance function across people, processes, controls.
• Build scalable operating model for growth and acquisitions.
• Partner with CEO and leadership to improve commercial decisions.

Skills

Interim CFO

Private equity experience

Post-acquisition experience

FP&A

Board reporting

Commercial finance

M&A integration

Growth planning

Financial controls

Leadership

Job description

The opportunity

Our client is an upper mid-market private equity fund that has recently acquired a professional services platform and is now seeking a proven interim CFO to join the portfolio company at a critical point in the ownership journey. The successful candidate will be appointed by, and work closely with, the fund and portfolio leadership team to deliver the first 100 days post-acquisition, professionalise the finance function, and establish the financial infrastructure required to support ambitious organic and acquisitive growth.

This is a high-impact interim CFO assignment for an experienced private equity finance leader who can enter quickly, diagnose fast, bring control and confidence to the numbers, and execute at pace. The role requires someone who has done this before: stabilising and professionalising finance in a newly acquired sponsor-backed environment while creating the platform for growth.

Key responsibilities

• Lead the finance workstream of the post-acquisition 100-day plan, converting diligence findings and the investment thesis into a clear, measurable execution roadmap.
• Establish immediate confidence in financial information, including revenue, margin, cash, working capital, forecasting and underlying performance.
• Create a PE-quality reporting rhythm for the fund, board and management team, including board packs, KPI dashboards, weekly cash reporting, covenant visibility and forward-looking performance analysis.
• Professionalise the finance function across people, processes, systems, controls, data and governance, ensuring the business can operate with the discipline expected of an institutional-quality platform.
• Build a scalable finance operating model capable of supporting organic growth, margin expansion, multi-site complexity and future acquisition integration.
• Partner with the CEO and senior leadership team to improve commercial decision-making, pricing visibility, utilisation, profitability analysis and performance accountability.
• Prepare the business for a buy-and-build strategy, including acquisition readiness, integration planning, reporting harmonisation, group controls and post-deal performance tracking.
• Assess finance capability and structure, making immediate recommendations on team gaps, interim support, external advisers and permanent hiring requirements.
• Drive improvements in systems, data quality, chart of accounts, management information, budgeting, forecasting and finance process automation.
• Act as a trusted finance partner to the private equity fund, lenders, board and external advisers, bringing transparency, pace, grip and commercial judgement.

Candidate profile

• Proven interim CFO with a strong track record in private equity-backed businesses, ideally including multiple post-acquisition, transformation or value creation assignments.
• Experience operating in professional services, people-based, human capital, consultancy, compliance, technology-enabled services, financial services, or other asset-light business models.
• Demonstrable experience delivering 100-day plans, finance professionalisation, reporting upgrades or value creation agendas in newly acquired or fast-scaling platforms.
• Strong command of cash, working capital, forecasting, management reporting, FP&A, controls and board-level financial communication.
• Commercially sharp and strategically minded, with the ability to move beyond accounting and become a value creation partner to the CEO and sponsor.
• Credible at board and investor level, with the confidence to challenge, influence and make decisions in a demanding private equity environment.
• Hands-on enough to diagnose and fix the detail, but senior enough to design a finance function that can support a materially larger group.
• Experience supporting M&A, acquisition integration, multi-entity reporting or buy-and-build strategies would be strongly preferred.
• Immediately available or available at short notice, with the pace, judgement and resilience required to operate effectively in a demanding private equity environment.

Initial priorities

• Build trust with the private equity fund, CEO and board by rapidly establishing the true financial baseline of the business.
• Deliver a practical 100-day finance roadmap covering reporting, controls, cash, people, systems and growth readiness.
• Introduce weekly cash visibility, robust short-term forecasting and clear working capital discipline.
• Deliver PE-quality board reporting and KPI visibility that enables better decisions around growth, margin, pricing and investment.
• Stabilise and accelerate month-end close, reporting quality and financial control.
• Define the finance operating model required to support the next stage of organic growth and acquisition-led expansion.