Part-time CFO services: How the scope changes from seed to Series A to Series B
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Key Takeaways
- 74,600 financial manager positions open each year in the United States. At a median salary of $161,700, a full-time hire is out of reach for most seed-to-Series-A companies. The part-time CFO model exists specifically for that gap.
- At seed stage, the engagement runs eight to sixteen hours a month: monthly close, thirteen-week cash flow forecast, and a one-page board update. The scope does not yet include a three-statement model or fundraise preparation.
- Series A expands to sixteen to thirty-two hours a month, a full board pack delivered 48 hours before every meeting, a three-statement model with scenario analysis, and unit economics tracked by cohort.
- Series B introduces audit readiness as a requirement, NRR cohort analysis by acquisition channel and vintage, and a three-year model with an EBITDA pathway. This is where the boundary between part-time and full-time starts to be tested.
- The signal to move to a full-time CFO is not stage or revenue. It is what the CFO is being asked to do in the six months after Series B closes.
74,600 financial manager positions open each year in the United States, with employment projected to grow 15 percent from 2024 to 2034, five times the average growth rate for all occupations. At a median salary of $161,700, a full-time financial manager is out of reach for most seed-to-Series-A companies. The part-time CFO model exists specifically for that gap: the period between the founder managing the books and the company being able to justify a full-time hire. What the engagement covers in that gap is not static. It changes materially as the company grows.
This guide covers what a part-time CFO delivers at seed, Series A, and Series B, and what signals the transition to a different structure. For a full breakdown of service scope, see the founder's guide to fractional CFO services.
What does a part-time CFO do at seed stage?
At seed stage, the part-time CFO engagement runs roughly eight to sixteen hours a month. The scope is narrow by design. The company does not yet have the transaction volume, the investor reporting requirements, or the financial complexity that justifies more.
Three deliverables anchor the seed-stage engagement. The monthly close keeps the books accurate and closed within five business days. The thirteen-week cash flow forecast, updated weekly, turns the bank balance from a snapshot into a planning tool. A one-page board update carries the key metrics with a short CFO narrative.
The seed-stage engagement does not include a full three-statement model, cohort analysis, or fundraise preparation. The CFO builds the foundation that makes those deliverables possible at Series A.
How does the scope change at Series A?
Series A expands the engagement in three directions: hours, deliverables, and investor-facing work.
Hours move to sixteen to thirty-two a month. The board update becomes a full pack covering financial statements, the KPI dashboard, variance commentary, and a forward-looking narrative, delivered 48 hours before every board meeting. The CFO attends and fields investor questions directly.
The financial model expands from a basic twelve-month cash flow view to a three-statement model with a rolling twelve-month forecast and scenario analysis. Every material hiring or pricing decision runs through the model before it is made. Unit economics are tracked by cohort, not in aggregate, because that is what Series B investors will pull apart in diligence.
Fundraise preparation enters the scope. The CFO begins building audit-ready financials and data room components twelve months before the next raise opens. For what that preparation looks like specifically, see how to prepare your financials for a Series A raise.
Part-time CFO
A senior finance executive who provides CFO-level services on a part-time basis, typically through a retainer rather than a full-time employment contract. The role owns the financial model, board reporting, and fundraise support, scaling the hours and deliverables to the company's stage.
How does the scope change at Series B and beyond?
Series B changes the engagement in ways that are qualitative, not just quantitative. The deliverables become more sophisticated, the investors ask harder questions, and the CFO's time shifts toward work that cannot be systemised.
Audit readiness becomes a requirement rather than preparation. Series B investors frequently require two years of audited financial statements, and the close process has to be clean enough to support that audit without rework.
NRR cohort analysis replaces blended retention metrics. Investors examine net revenue retention by customer size, acquisition channel, and contract vintage, and the part-time CFO builds and maintains that view well before the Series B process opens.
The three-year model with an EBITDA pathway becomes the central document in investor conversations. This is where the boundary between a part-time engagement and a full-time hire starts to be tested, not by the deliverable itself, but by the hours required to produce and defend it through a live fundraise.
Rolling forecast
A financial model that extends a fixed number of months forward regardless of where the company is in the calendar year. A twelve-month rolling forecast always covers the next twelve months, updated monthly as actuals replace projections. Unlike an annual budget, which becomes less useful as the year passes, a rolling forecast stays a current planning tool throughout. Part-time CFO engagements typically introduce it at Series A, replacing the simpler thirteen-week cash flow model used at seed.
Worked example
A usage-based developer infrastructure startup engages a part-time CFO at seed, $700K ARR, on a twelve-hour-a-month retainer. The work is the monthly close, a thirteen-week cash flow forecast, and a one-page board update. That is the right scope for the stage; the company has one revenue line and no investor reporting obligations yet.
Eighteen months later the company is at $3.1M ARR and opening a Series A. The same retainer no longer fits. The CFO moves to roughly twenty-four hours a month, rebuilds the model as a three-statement forecast with scenarios, and splits the single usage-revenue line into cohorts so the board can see retention by signup quarter. The board pack goes from one page to a full document delivered 48 hours ahead of each meeting.
Nothing about the provider changed. The scope did, because the company did. The founder who had assumed the seed retainer would simply carry forward learned that the engagement scales in deliverables and hours, not just price, and that planning for the step-up twelve months out is what keeps the Series A data room from being built in a panic.
Is a part-time CFO the same as a fractional CFO?
In most contexts, yes. Both describe a senior finance executive providing CFO-level services without a full-time employment commitment. Where providers draw a distinction, a part-time CFO may work a fixed weekly schedule, while a fractional CFO more commonly works a defined number of days per month across multiple clients. The deliverables and scope are the same. What matters is the seniority of the person running the engagement and what they are accountable for each month.
When should you move from a part-time to a full-time CFO?
The signal is not stage or revenue. It is what the CFO is being asked to do in the six months after a Series B closes. If multi-entity consolidation, international tax, or public-company-style reporting is becoming the norm, the engagement has outgrown the part-time model. If the workload stays within what a retainer can absorb, the transition can wait. For the signals that tell you the model is no longer sufficient, see the nine signals it is time to hire a CFO.
At Fintera, part-time CFO engagements are structured around what the company needs at each stage and what the next twelve months require. No pitch. No pressure. Just the honest read on where you are.