What Is an Interim CFO?

Introduction

Financial leadership gaps are high-risk moments for any company. When a CFO departs unexpectedly, fundraising is underway, or financial instability threatens momentum, waiting months for a permanent hire is rarely an option.

At these inflection points, companies need immediate, senior-level financial leadership with full authority to stabilize operations, restore confidence, and guide the business through transition.

This is where an interim CFO plays a critical role.

An interim CFO is a seasoned financial executive who steps into the business full-time for a defined period, typically three to nine months. They lead the finance function during transitions, crises, or major initiatives and prepare the organization for its next phase of growth or permanent leadership.

What Is an Interim CFO?

An interim CFO (Chief Financial Officer) is a senior financial executive who temporarily assumes full responsibility for a company’s finance function. Unlike fractional CFOs, who work part-time on an ongoing basis, interim CFOs are embedded full-time and operate with full executive authority.

They are not advisors. They are operators.

Key distinctions

Interim CFO vs Full-Time CFO
Interim CFOs provide immediate leadership without a long-term employment commitment or extended search process.

Interim CFO vs Fractional CFO
Fractional CFOs support ongoing strategy part-time. Interim CFOs step in full-time to lead finance during a defined transition or period of urgency.

Interim CFO vs Controller
Controllers focus on financial operations and reporting. Interim CFOs own financial strategy, capital decisions, and executive-level outcomes.

Interim CFO vs Consultant
Consultants recommend. Interim CFOs execute. They lead teams, manage budgets, and are accountable for results.

In practice:
As an example, a venture-backed company preparing for acquisition might bring in an interim CFO for six months to stabilize reporting, manage diligence, work directly with bankers and investors, and ensure financial readiness through close, without the concern or expectations of an ongoing role post-close..

What Does an Interim CFO Do?

An interim CFO’s mandate is to bring clarity, stability, and momentum during periods of uncertainty. Their responsibilities typically span five core areas:

Stabilizing Financial Operations

  • Assess financial systems, controls, and reporting accuracy
  • Identify cash flow risks and immediate exposure
  • Ensure payroll, vendors, and obligations are met without disruption

Leading Through Transition

  • Take full ownership of the finance function and team
  • Maintain morale and accountability during leadership changes
  • Act as a trusted partner to the CEO, board, and investors

Strategic Financial Leadership

  • Build or refine financial models and forecasts
  • Guide pricing, margin improvement, and cost structure decisions
  • Align financial strategy with business objectives

Fundraising, Transactions, and Diligence

  • Prepare financials for fundraising, audits, or M&A
  • Manage investor, lender, and advisor relationships
  • Lead diligence processes with accuracy and credibility

Preparing for Long-Term Success

  • Document processes and institutional knowledge
  • Hire, mentor, or reorganize finance team members
  • Support the search for and handoff to a permanent CFO

Benefits of Hiring an Interim CFO

When financial leadership is missing or overwhelmed, delays are costly. Interim CFOs help companies avoid compounding risk while creating space for thoughtful long-term decisions.

Key benefits

Immediate leadership continuity
Finance remains stable and credible during executive transitions.

Speed to impact
Interim CFOs can be in seat within days or weeks, not months.

Objective perspective
Outside leadership without historical bias or internal politics.

Execution under pressure
Ideal for fundraising, restructures, audits, or crises.

Clean handoff
Systems, documentation, and teams are prepared for permanent leadership.

When Should a Company Hire an Interim CFO?

An interim CFO is most valuable when:

  • A CFO or senior finance leader departs unexpectedly
  • The company is preparing for fundraising, acquisition, or audit
  • Financial instability threatens operations or investor confidence
  • The CEO or founder is temporarily covering finance responsibilities
  • The business is undergoing restructuring or turnaround

For funds, interim CFOs are often deployed to stabilize portfolio companies during critical moments without committing to permanent hires too early.

How Long Does an Interim CFO Engagement Last?

Most interim CFO engagements range from three to nine months, depending on the situation:

  • Short-term (1 to 3 months): Crisis stabilization or temporary coverage
  • Mid-term (4 to 6 months): Fundraising preparation or organizational redesign
  • Long-term (6 to 9+ months): Full financial transformation or leadership rebuild

How Much Does an Interim CFO Cost?

Interim CFO pricing reflects the seniority, intensity, and urgency of the role:

  • Monthly retainers: $25,000 to $50,000+ for full-time engagement.  This could be less if the needs can be filled on an Interim and part-time basis (if the needs are not full-time.)
  • Project-based engagements: $50,000 to $150,000+ for defined outcomes

While the investment can be significant, the cost of prolonged financial instability is often far higher in lost valuation, delayed capital, and operational disruption.

Interim CFO vs Alternative Solutions

Role

Engagement Type

Focus

Best For

Interim CFO

Full-time, temporary

Financial leadership and stability

Transitions or crises

Fractional CFO

Part-time, ongoing

Strategic financial oversight

Growth-stage companies

Controller

Full-time

Financial operations

Day-to-day execution

Accountant

Ongoing

Compliance and reporting

Historical financials

Consultant

Project-based

Advisory

Narrow initiatives

Why Choose Size.vc for Interim CFO Leadership

At Size.vc, interim leadership is not treated as a stopgap. It is treated as a strategic intervention designed to protect value and position companies for what comes next.

The Size.vc approach

  • Proven CFOs with experience across growth, fundraising, and transactions
  • Rapid placement to minimize disruption
  • Full executive integration with ownership of outcomes
  • Alignment with founders, boards, and investors

Get Started with Interim CFO Leadership

Financial leadership gaps do not need to slow your business down.

If your company is navigating executive turnover, financial instability, or a high-stakes transition, an interim CFO can provide the leadership needed to move forward with confidence.

Book a consultation today to connect with Size.vc and get matched with the right interim CFO for your situation.

Frequently Asked Questions

What is an interim CFO?
An interim CFO is a senior financial executive who temporarily leads a company’s finance function during transitions or periods of instability.

How is an interim CFO different from a fractional CFO?
Interim CFOs are full-time temporary leaders. Fractional CFOs are part-time, ongoing partners.

How long does an interim CFO typically stay?
Most engagements last between three and nine months.

When should a company hire an interim CFO?
During leadership turnover, fundraising, audits, restructures, or periods requiring immediate financial leadership.

Where can I find a qualified interim CFO?
Size.vc connects founders and investors with vetted interim CFOs who have led finance functions through high-growth and high-pressure environments.