What Does a Fractional CFO Actually Do? The first 90 days, week by week
Contents
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Day one, the CFO asks for your accounting login, your bank statements, and your last three months of payroll. Not your pitch deck. Not your growth targets. The books first, because everything else is built on top of them, and in most pre-CFO finance functions, the books have problems that compound quietly until someone looks.
This is the week-by-week breakdown of what a fractional CFO actually works on across the first 90 days: what gets built, in what order, and what changes in the business by the time each phase closes. The previous two guides in this series covered what the role is and what sits on a retainer. This one is the sequence.
There is a reason the timing of this engagement matters more than most founders realise. The US Bureau of Labor Statistics projects financial manager employment to grow 15 percent between 2024 and 2034, five times faster than the average for all occupations. Demand for financial leadership at growing companies is outpacing supply. Founders who wait for that leadership to come to them are already behind the ones who built the infrastructure early.
49.2%Five-year survival rate for new US employer establishments, 1994-2022 |
67.7%Share of new employer establishments that reach their second year |
1.3MNew business establishments opened in the US in 2023 alone. |
What separates companies that make it past year five is rarely the product. It is whether the financial infrastructure existed to catch problems early enough to fix them. A fractional CFO engagement in the first 90 days is, in practical terms, the installation of that infrastructure.
The Three-phase arc
The 90 days divide cleanly into three phases. Each phase creates the conditions the next one requires. You cannot build a reliable model on inaccurate books. You cannot prepare for a raise if the model has not been stress-tested.
1. MONTH ONE · WEEKS 1 TO 4Get the numbers right before anything else The first four weeks are diagnostic. The CFO reads what exists: the chart of accounts, how revenue is being recognised, what is off the balance sheet. The same structural gaps appear in almost every pre-CFO finance function. Books on cash basis instead of accrual. Payroll costs in the wrong category, making gross margin look cleaner than it is. Deferred liabilities not reflected in the runway calculation. Do I need a bookkeeper in place before the CFO starts? Yes. A fractional CFO works from your books, not instead of them. If bookkeeping is not current, the first two weeks go toward getting the books to a usable state rather than building anything forward-looking. When bookkeeping and CFO support come bundled on a single retainer, this sequencing happens automatically without any overlap cost. ● Financial diagnostic complete. Every account category reviewed and mapped correctly. Chart of accounts restructured if needed. ● Books migrated to accrual basis if still on cash. Under US GAAP, accrual is the required accounting basis for any serious investor conversation. Revenue is recognised when earned, not when cash is received. ● 13-week rolling cash flow forecast built from the actual bank balance. Burn rate and runway calculated precisely. The founder can state both numbers in under sixty seconds without opening three files. ● Gross margin recalculated correctly. Hosting, contractor, and support costs that belong in cost of goods sold are moved there. The resulting margin number is the one investors will work from. A SaaS founder came into a Fintera engagement with nine months of runway on paper. The month one diagnostic found hosting costs sitting above the gross margin line. Moved correctly, gross margin dropped eight points. Runway recalculated to six months. The raise timeline moved up by ninety days. The number had been wrong for the better part of a year. |
2. MONTH TWO · WEEKS 5 TO 8Build the model investors will actually interrogate Once the books are clean, the forward-looking work begins. The CFO builds the three-statement model: income statement, balance sheet, and cash flow, mathematically linked so that a change in revenue flows through margin, burn, and runway automatically. A standalone revenue projection is not a financial model. This is the distinction that separates founders who get clean follow-up questions from those who get asked to come back in thirty days. What does the CFO actually need from me in week one? Access to your accounting software, your bank statements, a list of your top ten expenses, your current cap table, and a hiring plan if you have one. Most of the diagnostic work happens on the CFO's side. You will be pulled in for a thirty-minute call to align on what matters most in the next six months. From there, the month one deliverables run largely without you needing to be in the room. ● Three-statement model complete with monthly view for the next 18 to 24 months. Every assumption documented and defensible. ● Unit economics by channel or product line. CAC, LTV, payback period, and contribution margin calculated and segmented. ● Scenario planning: base case, upside, and downside. If growth comes in 20 percent below plan, what happens to runway? The answer should be prepared, not calculated live in a partner meeting. ● Burn multiple tracked. Net burn divided by net new ARR. Below 1.0 is excellent. Above 2.0 is a conversation to start before an investor does. |
3. MONTH THREE · WEEKS 9 TO 12Build the outputs the next six months depend on By week twelve, the books are clean and the model is stress-tested. Month three is about turning that foundation into the outputs that carry the business through the next six months. How many hours a month does this take from my calendar? In month one, three to four hours: onboarding, one diagnostic review, and a call to walk through the forecast. From month two onward, one monthly financial review of around ninety minutes plus ad hoc availability for investor questions or board prep. A good engagement runs without you in every meeting. You are in the decisions, not the data gathering. ● Board pack template built and first edition produced. Burn, runway, ARR, churn, and budget versus actuals in a consistent format, ready 48 hours before every meeting. This recovers four to five hours of founder prep every month. ● Cap table modelled across the next two rounds. Equity decisions made at seed have real consequences at Series B. ● Data room skeleton built. Financial history, three-statement model, cap table, and legal entity structure in one place. Adding to it during a live raise takes hours, not weeks. ● Investor Q&A preparation complete. The financial questions every Series A partner asks first, answered clearly before the first meeting. |
Week by week
Founders who skip month one and go straight to the model build on a bad foundation. Four things typically break it:
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Gross margin that looks clean but is not
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Runway calculated from forecast, not the actual bank balance
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Deferred liabilities that never make it onto the balance sheet
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A cap table never modelled forward, so dilution consequences only surface when it is too late
Week |
Primary deliverable |
What changes for the founder |
|
W 1 |
Financial diagnostic. Books reviewed, structural gaps identified, accrual migration started. |
First time seeing the actual burn number, not the estimated one. |
|
W 2 |
13-week cash flow forecast. Gross margin recalculated with the right cost allocation. |
Runway known to the week. Stop opening three files to answer one question. |
|
W 4 |
Chart of accounts finalised. Reporting infrastructure running. |
Books are now the foundation everything else is built on. |
|
W 6 |
Three-statement model complete. Unit economics by channel. |
First time the investor story has defensible numbers behind every line. |
|
W 8 |
Scenario planning complete. Burn multiple tracked monthly. |
Can answer the Series A downside question clearly before being asked. |
|
W 10 |
First board pack produced. Cap table modelled across next two rounds. |
Board meeting prep drops from a weekend to an afternoon. |
|
W 12 |
Data room skeleton built. Investor Q&A preparation complete. |
Ready to open a raise process without scrambling to become ready first. |
What if we are not raising for another 12 to 18 months?
The 90-day arc serves the business regardless of whether a raise is imminent. The burn multiple informs hiring decisions. The unit economics inform pricing. The board pack makes every leadership conversation more grounded. The fundraise makes the work more urgent, not more valuable. The financial infrastructure is useful from day one of having it, which is why the right time to build it is earlier than most founders act on.
The infrastructure is the same whether the raise is six months away or eighteen. The only difference is how much runway you have to build it properly.
At Fintera, every engagement follows the same three-phase arc. The CFO partner assigned from day one is briefed on your stage and your fundraising timeline before the first call. The infrastructure built over 90 days is yours, documented, and accessible to you beyond the engagement. The model does not live on one person's laptop.
See what the first 90 days looks like for your stageA call will cover your current setup, identify the gaps, and map what month one would produce. No pitch. No pressure. Just the honest read on where you are. |