The short answer
The difference is not qualification, it is accountability. A management consultancy analyses and recommends – the output is a concept that someone inside the company has to implement. An interim CFO decides and leads – answerable to shareholders, banks and the team, and responsible at month-end for the numbers being there.
Both are legitimate. The only question is: is an answer missing, or is someone missing to implement it?
The test
Three questions usually settle it in five minutes.
- Do we know what needs to be done? If not – and the question is strategic rather than operational – a consultancy can be the right route. If yes, what is needed is not analysis but capacity and decision rights.
- Who approves payments and signs off the reporting? If that person is missing, no concept helps. A consultancy does not take on that role.
- What happens after the project? A concept that nobody inside the company owns stays a document.
What the consultancy does better
It brings comparative knowledge from many companies, method, and a team that moves a lot of analysis in a few weeks. For a market assessment, a strategy question or a valuation methodology that is exactly right – and in special situations such as a restructuring opinion under IDW S 6, the German standard for going-concern restructuring opinions, a specialised adviser or auditor is simply required.
The numbers for that still come from inside the company. The better they stand, the shorter and cheaper the opinion. That is the part an interim CFO delivers – see finance in a restructuring.
What the interim CFO does better
They are part of the organisation, not a guest in it. They lead the team, prioritise, approve, and speak to the bank and the shareholders as the person accountable, not as the adviser to the person accountable. They work in the day-to-day rather than observing it.
And they are usually available faster: first suitable profiles within 24 hours, start a few days after selection. A consulting project needs scoping, a proposal and a team to be assembled.
The cost question, asked properly
An interim CFO sits at €1,400 to €2,500 per day – one person who does the work. A consulting team costs a multiple of that per day and delivers markedly more analysis in a short time.
The expensive mistake is not choosing one or the other. It is buying a concept and then discovering that nobody is there to implement it – and commissioning the implementation half a year later as a second project.
Side by side rather than against each other
In larger undertakings both run in parallel, and it works well when the roles are cleanly separated:
- Exit preparation: the audit firm produces the financial factbook, the interim CFO delivers the consolidated numbers and answers the follow-up questions. That is how the B2B software group case was set up.
- Restructuring: the adviser writes the restructuring opinion, the interim CFO manages liquidity and leads the bank conversations.
- System implementation: the implementation partner provides the technology, the interim CFO owns the chart of accounts, the accruals and the test close.
The dividing line is always the same: who is accountable for the result? That question belongs before the start, not in the first escalation.
A note for readers outside Germany
German restructuring practice has a formal document at its centre: the IDW S 6 opinion, prepared by an auditor or specialised adviser, which banks expect before they extend or restructure facilities. No interim CFO writes it – but every one of them supplies the data it is built on, and the quality of that data decides how long and how expensive the opinion becomes.
Frequently asked questions
Isn't an interim CFO just another external adviser?
No, and the difference is contractual. The interim CFO takes operational responsibility for a defined area, holds decision and approval rights and leads staff. An adviser has none of that.
When do I need both?
When a special task requires methodological expertise – an opinion, a valuation, a system selection – and the day-to-day has to keep running at the same time. Then the interim CFO carries the operation and delivers the data basis, and the specialist does their work.
Does nugrow write restructuring opinions?
No. An IDW S 6 opinion comes from an auditor or a specialised adviser. We provide the data basis without which it cannot be written.
What about the transaction advisory arms of the large audit firms?
In a due diligence they are often a given – on both sides. They review and report. Who owns the month-end close and answers the data room questions in the meantime is a different role.
Read on
- Interim CFO or executive search – the other route to closing the same gap.
- Interim CFO, CFO as a service or permanent hire.
- References – twelve mandates, several with advisers working in parallel.
- Pricing.
Sources and status
The article is based on nugrow's mandate practice. Status: September 2026. It is an overview and does not replace legal or tax advice.