The finance leader has left.
Reporting still has to land, the board still meets, and the auditor and the bank still need someone to call. Recruitment for a permanent replacement typically runs three to five months, and the gap is the problem.
Interim CFO
Interim CFO cover for growing startups and international technology companies
Numminen Advisory provides interim CFO cover to growing technology companies. An interim CFO holds the finance seat for a defined period, usually because the CFO has left or a transaction needs a senior pair of hands until it closes.
The engagement is scoped around what has to keep running and what has to be handed over. Both are agreed before it starts.
6months
StartHandover
When you may need an interim CFO
Four situations, and the scope differs in each.
A transaction is live.
A round, a sale or an acquisition needs a senior pair of hands on the numbers from the data room through to close, without pulling the existing team off the month.
Diligence has exposed something.
Remediation at pace, while the transaction is running and the numbers are pulling apart under scrutiny.
The group has outgrown its finance function.
A step change has arrived faster than the hiring plan, and someone has to hold the standard while the permanent structure is built underneath.
AI in finance
How AI changes interim CFO work
An interim CFO has weeks, not months, to understand a finance function. At Numminen Advisory, AI shortens that learning curve: it maps processes to owners, ages open items and drafts handover notes from the first week. Joanna Numminen spends the engagement on the decisions a vacant CFO seat leaves open.
| Finance task | What AI does now | What stays with the CFO |
|---|---|---|
| Taking over the function | Maps finance processes and their owners from the ledger, the close checklist and past reports. | Deciding what to fix first, and who owns it. |
| Open items | Ages open items by entity each morning and names an owner for each. | Which items carry real risk, and what to escalate. |
| Month-end close | Runs the close checklist step by step and flags what is late. | Sign-off of the close and the estimates behind it. |
| Handover | Drafts the handover file from the process map and the open items register. | The recommendation on the permanent hire, and the handover itself. |
How we run it
- Each interim engagement opens as its own project in the workspace Joanna built, with the company’s context loaded in the first week.
- Read-only integrations let the systems be connected on day one without changing anyone’s access.
- The handover file is kept current throughout, so the permanent CFO inherits a documented function.
What the interim CFO engagement covers
When you engage Numminen Advisory you secure both urgent financial leadership cover and your long-term continuation planning.
First
Keep it running.
The monthly close lands on its date. Board and investor reporting goes out. Banks, auditors and the accounting firm have one person to deal with.
Second
Stabilise what is fragile.
The things that were being held together by the person who left get documented and made repeatable, starting with whatever a transaction or an audit will touch first.
Third
Hand over cleanly.
A permanent CFO or controller arrives to a function that is documented rather than described, which is the difference between a handover and an archaeology project.
Do you need a part-time or an interim CFO?
Here are the three common types of external financial leadership you should compare:
Fractional
Ongoing and part-time, typically two to seven days a month, with no end date. The right shape when the work is senior but intermittent.
Interim
A defined period with an end, at a higher intensity, usually full weeks rather than days. The right shape when a seat is empty or a transaction is running.
Outsourced
Usually a package sold by an accounting firm alongside bookkeeping. A different product, because the seat sits inside the provider’s organisation.
Interim CFO
Behind the practice
Numminen Advisory is founded and run by Joanna Numminen. Fifteen years in finance inside international technology companies, from audit at Deloitte through controller and finance director roles to a CFO seat.
ACCAQualified since 2017Member of the Association of Chartered Certified Accountants
MScInternational Accounting and FinanceBayes Business School, City, University of London
MAEconomics, majoring in Controlling and Corporate FinanceKraków University of Economics
What it costs
Interim cover is quoted against the scope and the expected duration, from a baseline day rate of 1 450 euros. The quote is fixed before the engagement starts. Amounts exclude VAT.
Where an engagement is clearly a defined project with an end deliverable rather than a seat to hold, it is priced as a fixed-fee project instead. Which of the two it is usually becomes clear during the first call.
Track record
Our track record as a finance leader
Due diligence and integration. Supported an applied AI group through financial due diligence and post-deal integration by a global semiconductor company, after building its finance function from the ground up.
Group consolidation. Led end-to-end group consolidation across every entity in a fast-scaling multi-country group, owning the full close cycle.
Three frameworks at once. Ran Finnish reporting, IFRS and US GAAP concurrently off a single underlying ledger in a B2B SaaS group, alongside a control framework built from scratch.
Venture rounds. Prepared the financial materials and ran the due diligence for venture rounds, from the company’s side of the table.
Systems. Owned NetSuite as product owner across offices in five countries, including the implementation projects and not only the specification.
Numminen Advisory is founded and run by Joanna Numminen. ACCA qualified since 2017, after training in audit at Deloitte. MSc in International Accounting and Finance, Bayes Business School, City, University of London. MA in Economics majoring in Controlling and Corporate Finance, Kraków University of Economics.
Common questions
What is an interim CFO?
An interim CFO is an experienced finance leader who holds the CFO seat for a defined period, with an agreed end. The usual reasons are a departure, a transaction, or a step change that has arrived ahead of the permanent hire.
How quickly can you start?
Faster than a recruitment process, which is most of the point. The first call establishes whether the work is a seat to hold or a project to run, and the scope follows from that.
How long do interim engagements run?
Usually between three and nine months. Long enough to cover a recruitment cycle or a transaction, short enough that the end date stays real rather than drifting into a permanent arrangement nobody decided on.
Is this the same as a fractional CFO?
No. Fractional work is ongoing, part-time and open-ended. Interim work is a defined period at a higher intensity, with a handover built into the scope from the beginning.
Can you work alongside our existing finance team?
Yes, and usually that is the arrangement. A controller and an accounting firm generally stay exactly where they are. What has gone missing is the layer above them, and that is the layer being covered.
What happens at the end?
A documented finance function, a handover to whoever takes the seat permanently, and a written note of what was left unfinished and why. The last of those matters more than it sounds.
What language does the work run in?
The work runs in English, which is the language of the data room, the diligence process and the investor relationship.