What a startup CFO does and the fractional option
A CFO owns board-level finance: board packs, runway, investor reporting and the financial model that ties the cap table to headcount and burn. A full-time senior hire is expensive early in a company's life, so funded startups often use a fractional (part-time) CFO to hold that function without the cost of a permanent senior salary. The question is not "do we need a CFO?" but "at what scale and in what form?"
Full-time vs fractional vs an outsourced finance function
Three models serve different stages. None is universally correct; the right answer depends on your current funding stage, board obligations and reporting complexity.
| Model | What you get | When it fits | Cost basis |
|---|---|---|---|
| Full-time CFO | A permanent senior finance leader embedded in the business, attending every board meeting, leading all investor conversations and managing the finance team. | Post-Series B or when complexity genuinely demands daily senior presence: large headcount, multiple entities, public-market preparation, complex M&A. | Salary, benefits, equity. Cost varies substantially by seniority and market; no reliable public UK startup benchmark is cited here. |
| Fractional CFO | A senior finance leader working a defined number of days per month. Delivers board packs, investor reporting, runway modelling and strategic advice without being present full-time. | Funded startups from seed through Series A/B that have a board to report to but are not yet at the scale to justify a full-time hire. The most common model for this cohort. | Day rate or monthly retainer, scoped to engagement. Cost varies by seniority, provider and days. Start a conversation to understand what fits your stage. |
| Outsourced finance function | Accounting, bookkeeping, management accounts and compliance handled by an external team. Does not usually include board-level strategic finance or investor-facing work. | Pre-revenue or very early-stage startups that need compliance and clean accounts but do not yet have a board expecting a monthly pack or an active investor relationship to manage. | Fixed monthly fee or scope-based. Lower than either CFO option; covers the operational finance layer, not the strategic one. |
Many funded startups run both: an outsourced finance function handling the operational layer and a fractional CFO sitting above it for board and investor work. The two are complementary, not competing.
When does a startup actually need a CFO?
The honest answer is: not as early as many founders assume. A pre-seed company with one investor and no board pack obligation does not need a CFO. The triggers that change that calculus are specific.
| Trigger | Why it demands senior finance |
|---|---|
| Board expects a monthly pack | Investors in funded startups expect a monthly board pack: P&L, cash, runway, headcount, key metrics. Producing one to board standard is a CFO-level task. |
| Upcoming raise (Series A or beyond) | Investor due diligence, financial model stress-testing, data-room preparation and term-sheet negotiation all require someone who has done this before. |
| Scaling headcount and burn | When your monthly burn is material and growing fast, you need a model that connects hiring decisions to runway in real time, not a spreadsheet updated quarterly. |
| Complex reporting obligations | R&D claims, EMI grant notifications, VAT registration and EIS compliance all have strict deadlines and interact with each other. A CFO models these into the finance calendar so nothing is missed. |
| Multi-entity or international structure | Holding companies, overseas entities, transfer pricing or a US flip all introduce complexity that generic bookkeeping cannot handle. |
If none of these apply, your current finance setup is probably sufficient. The CFO conversation becomes urgent the moment even one of them does.
What CFO pay looks like at market
This is the question most founders ask first, and it is the hardest to answer honestly. CFO compensation for funded startups varies enormously by several factors.
Seniority and background. A first-time CFO from an accounting background commands different terms than a serial CFO who has run finance through two exits. The gap is substantial.
Full-time vs fractional. A full-time hire carries a salary, benefits and usually an equity component. A fractional CFO is typically day-rated or on a monthly retainer scoped to the number of days engaged. Fractional arrangements are almost always materially cheaper than a full-time hire of equivalent seniority, particularly at pre-Series B stage.
Scope and days. A fractional CFO doing two days a month for a small Seed-stage company is a different engagement from one running finance for a 50-person Series A company ahead of a raise. Cost scales with scope.
Market and timing. Startup finance talent markets move. No public benchmark cited here is current or granular enough to be useful; the figures that circulate are usually out of date, cover a wide range, and do not segment by stage or fractional vs full-time with enough precision to be actionable.
The right way to understand cost for your situation is to have a direct conversation. We do not publish a pricing schedule on this page; that conversation happens on our fractional CFO service page.
Where the CFO function meets tax and equity work
For a funded startup, the finance function is not just about management accounts. Several tax and equity obligations have timing or scale triggers that must be modelled into the financial plan. A CFO who does not know these will miss them.
R&D credit timing
The merged R&D scheme gives a 20% above-the-line expenditure credit on qualifying spend for accounting periods beginning on or after 1 April 2024. That credit is material for an R&D-intensive startup and needs to be modelled into runway at the point the spend is incurred, not retrospectively. First-time claimants must also notify HMRC within six months of the period end; missing the window kills the claim for that year. A CFO builds the R&D claim calendar into the finance function. See our R&D tax claims service.
EMI option pool in headcount planning
An EMI scheme allows up to £250,000 of unexercised option value per employee and £3m across the company, with gross assets of no more than £30m and fewer than 250 FTE. These limits are planning constraints. A CFO modelling a headcount build needs to know how much EMI headroom remains, which employees are approaching their individual limit, and at what point the company might breach the qualifying tests. Leaving this to HR creates gaps. See our EMI scheme setup service.
VAT registration as ARR scales
For a SaaS company, VAT registration is mandatory once rolling 12-month UK taxable turnover reaches £90,000. For SaaS with overseas B2B revenue, the place-of-supply and reverse-charge rules may mean that international revenue does not count toward the threshold in the same way. A CFO models the VAT registration point as ARR grows so it is not hit unexpectedly mid-quarter. See our VAT for SaaS: place of supply guide and our core compliance service.
SEIS and EIS raise readiness
If you are raising under SEIS or EIS, the compliance calendar starts at closing, not at exit. The compliance statement cannot be filed immediately; SEIS requires trading for at least four months or 70% of the raise spent. A CFO who tracks the investment close date and the qualifying conditions means you do not miss the filing window that unlocks investor certificates. See our funded startups hub.
Choosing a fractional CFO for a funded startup
Not every fractional CFO is the right fit for a funded startup. Several things to look for.
Board-pack experience. Have they produced monthly board packs for VC-backed companies? The format, cadence and investor expectations are specific; a CFO who has only worked in corporate finance or large-company settings may not have done this.
Raise experience. Have they run a finance process through a Series A or B? Data rooms, model stress-tests, investor queries and term-sheet mechanics are skills that come from having done it, not from theoretical knowledge.
Tech and SaaS fluency. SaaS metrics (ARR, MRR, churn, LTV/CAC, burn multiple) need to be native to the CFO, not learned on the job. A generalist finance background is not enough for a SaaS company's board pack.
Tax and equity join-up. Your CFO should understand how R&D credits, EMI grants and EIS compliance integrate into the financial model and calendar. These are not separate to finance for a funded startup; they are part of it.
Our fractional CFO service is designed specifically for funded UK startups. It covers board packs, investor reporting, runway and the join-up with R&D, EMI and SEIS/EIS compliance. Start the conversation there.
For the revenue side of the finance function, see our guide to SaaS revenue recognition under UK accounting standards.
FAQ
What does a startup CFO do?
A startup CFO owns the board-level finance function: monthly board packs, runway forecasting, investor reporting, financial modelling, and the join-up between the cap table, R&D claims, VAT registration and headcount planning. Below a certain scale, that function can be held fractionally rather than full-time.
How much does a fractional CFO cost?
Cost depends on seniority, scope, days per month and the provider. We do not publish a day rate on this page. The right way to understand what a fractional CFO arrangement costs for your company is to start a conversation. See our fractional CFO service page.
When should a startup hire a CFO?
The clearest triggers: your board expects a monthly pack, you are preparing a Series A or B, burn and headcount are scaling fast, or your reporting obligations have become too complex for your existing team. Earlier-stage companies often do not need a CFO yet.
Full-time vs fractional CFO: which is right for a funded startup?
A full-time CFO makes sense once you have the complexity and revenue to justify the cost of a permanent senior hire. Most pre-Series B funded startups are better served by a fractional arrangement that gives them senior finance leadership without the overhead, scaling up as the company grows.
Can a fractional CFO handle our R&D claim and EMI scheme?
A fractional CFO models R&D credit timing and EMI headroom into runway and headcount planning. The detailed claim preparation and scheme setup are specialist tasks handled through our R&D tax claims and EMI scheme setup services.
Use our founder dividend vs salary calculator to model your own extraction alongside these decisions, and explore our SaaS companies hub and funded startups hub for the wider finance picture.