Scenario Modelling a SaaS Raise: Base, Bear and Bull (2026)
A virtual CFO's method for three-case modelling ahead of a SaaS raise: the assumptions worth flexing, runway per case, the bear-case test, and the story per…
When a SaaS founder raises, the investor is not buying the plan; they are buying the range of plausible outcomes and the founder’s grip on it. A single projection, however confident, signals either naivety or spin. Three well-built cases, base, bear, and bull, signal a founder who understands the levers and has thought about what happens if they move. This is a virtual CFO’s method for building those three cases specifically for a raise, which is a different job from operating scenarios or the model’s structure.
Published: July 2026
The temptation in scenario modelling is to flex everything, which produces three cases that differ in a hundred small ways and illuminate nothing. Disciplined scenario work flexes only the few assumptions that really move the outcome and holds the rest constant, so the difference between cases is legible and each case tells a clear story.
For a SaaS raise, the assumptions worth flexing are usually four: new ARR growth (how fast new business comes in), churn (how much of the base leaks away), sales hiring ramp (how quickly new reps reach productivity, which drives both cost and future growth), and CAC drift (whether acquisition gets more expensive as you scale, which most SaaS businesses experience). These four move runway and the growth trajectory more than anything else. The assumptions to hold constant are the structural ones, gross margin, pricing architecture, the broad cost base, because flexing them muddies the comparison without adding insight. Getting the list of flexed assumptions right is most of the skill in scenario modelling, and it builds on the discipline of a fundraise-ready financial model and is a natural 90-Day Number ahead of a raise.
The three cases are not arbitrary optimism and pessimism; each is a coherent world. The base case is the founder’s honest expectation: the assumptions they actually believe, the plan they would run to. The bear case flexes the four assumptions unfavourably but plausibly, slower new ARR, higher churn, a slower hiring ramp, more CAC drift, to model what happens if the business underperforms without anything catastrophic. The bull case flexes them favourably but still plausibly, to model a strong-but-achievable outcome.
The discipline is plausibility. A bear case that assumes disaster and a bull case that assumes perfection are useless, because no one learns anything from the extremes. The useful cases are the realistic bad and the realistic good, the outcomes that could actually happen if the levers move in ways the business has seen before. Built this way, the three cases bracket the genuine range of the business, which is exactly what an investor wants to see.
The single most important output of the three cases is the runway and cash-out date in each. Runway is how many months of cash the business has at its burn; the cash-out date is when the money runs out if nothing changes. Because burn differs across the cases (the bear case burns faster relative to the growth it buys), the runway and cash-out date differ too, and showing all three tells the investor and the founder how much cushion the raise actually provides.
This is where scenario modelling connects to the raise size. The amount raised should give comfortable runway even in the bear case, not just the base, because a raise sized to the base case leaves the business exposed if the bear world arrives. Modelling the cash-out date per case is what lets the founder size the raise defensibly: enough to reach the next fundable milestone even if things go moderately wrong, which is a far stronger position than a raise that only works if the plan lands.
The sharpest question scenario modelling answers is the bear-case test: does the bear case still reach a fundable milestone before the cash runs out? A business is fundable at the next round if it has hit the metrics the next investor will want to see, a revenue level, a growth rate, a retention figure. The bear-case test asks whether, even in the realistic bad outcome, the business reaches that milestone with the cash this raise provides.
If the answer is yes, the raise is well sized and the founder can defend it: even if we underperform, this money gets us to the next fundable point. If the answer is no, the business is raising too little, or the bear case exposes a plan that only works if everything goes right, which is exactly the fragility an investor will probe. The bear-case test is the honest stress test of the raise, and running it before the pitch means the founder has already answered the hardest question the room will ask. The Australian context for what a fundable next round looks like is covered in Australian Series A benchmarks.
Each case needs a one-line story for the deck, because investors think in narratives as well as numbers. The base case story is the plan: here is what we expect and why. The bull case story is the upside: here is what happens if our best levers work, and here is why that is achievable. The bear case story is the resilience: here is what happens if we underperform, and here is why we still reach the next milestone. Told this way, the three cases show an investor a founder who has thought past the pitch into the range of real outcomes, which builds far more confidence than a single polished projection.
Take a SaaS business at $3M ARR raising $6M. The base case assumes new ARR growth continuing at its current rate, churn steady, a sales hiring ramp of two quarters to productivity, and modest CAC drift; it reaches roughly $7M ARR in 24 months with about 30 months of runway on the raise. The bear case flexes those unfavourably, slower new ARR, churn ticking up, a three-quarter ramp, sharper CAC drift, and reaches around $5.2M ARR with runway tightening to about 22 months. The bull case reaches roughly $9M ARR with runway extending as efficient growth lowers relative burn.
The decisive read is the bear case: at $5.2M ARR in 22 months, does the business clear the bar for a Series B raise before the cash runs low? If a B round wants, say, $6M-plus ARR with healthy retention, the bear case falls just short, which tells the founder the $6M raise is slightly light for the downside and either the raise should be larger or the plan needs a lever that holds up better under stress. That insight, available only because the bear case was modelled, is worth more than any amount of base-case polish. It is the same three-case discipline as scenario modelling for ecommerce, applied to the specific question of a raise.
How is a raise scenario different from operating scenarios?
Operating scenarios model decisions like an inventory buy or a hiring plan; raise scenarios model the trajectory and runway the funding buys, to size the raise and tell the investor story. The question is specifically whether the raise gets the business to its next fundable milestone across a range of outcomes, which is a different job from the model’s structure or from operating what-ifs.
Which assumptions should I flex?
For a SaaS raise, usually four: new ARR growth, churn, sales hiring ramp, and CAC drift. These move runway and trajectory more than anything else. Hold structural assumptions like gross margin and pricing architecture constant, because flexing them muddies the comparison. Getting the flexed list right, few and high-impact, is most of the skill in scenario modelling.
What makes a good bear and bull case?
Plausibility. A bear case that assumes disaster and a bull case that assumes perfection teach nothing. The useful cases are the realistic bad and the realistic good, outcomes that could actually happen if the levers move in ways the business has seen before. Built this way, the three cases bracket the genuine range, which is what an investor wants to see.
What is the bear-case test?
The question of whether the bear case still reaches a fundable milestone before the cash runs out. If yes, the raise is well sized and defensible even under underperformance. If no, the business is raising too little or has a plan that only works if everything goes right. Running the test before the pitch means you have already answered the hardest question the room will ask.
How does this size my raise?
By showing the runway and cash-out date in each case. A raise should give comfortable runway even in the bear case, not just the base, so it carries the business to the next fundable milestone if things go moderately wrong. Sizing to the base case alone leaves the business exposed; sizing to survive the bear case is the defensible position.
Why does each case need a story?
Because investors think in narratives as well as numbers. The base story is the plan, the bull story is the achievable upside, and the bear story is the resilience, we still reach the next milestone if we underperform. Told this way, the three cases show a founder who has thought past the pitch into real outcomes, which builds more confidence than a single polished projection.
Can a virtual CFO build my raise scenarios?
Yes. Building base, bear, and bull cases on the right flexed assumptions, with runway and cash-out per case and the bear-case test run, is a defined deliverable and a natural 90-Day Number ahead of a raise. The output is a model you own that sizes the raise defensibly and arms you with the three-case story investors expect.
Sydney Virtual CFO is a Sydney-based virtual CFO service for founders running $2M to $15M businesses across SaaS, ecommerce, professional services, construction, and other low-volume, high-value industries. We deliver fixed-scope CFO engagements with a named deliverable on day 90: a 13-week cashflow forecast, a fundraise-ready financial model, a unit economics build, or a board reporting pack you can run on your own.
Our front-door product, the 90-Day Number, is fixed scope at $17,850 plus GST. We are one of the few project-based virtual CFOs in Australia, in a market built almost entirely on monthly retainers. No retainers without a deliverable. No 80-page reports. No theatre.
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This content is general information only, written for Australian founders running businesses in the $2M to $15M revenue range. It does not constitute tax, financial product, investment, or legal advice and should not be relied on as such. The work referenced is led by a Chartered Accountant (CA ANZ), but Sydney Virtual CFO is not a licensed tax agent, not a licensed financial adviser, and not authorised to provide personal financial advice. Tax obligations, accounting treatments, fundraise terms, and statutory requirements depend on your individual circumstances. For advice specific to your business, contact the team directly or consult a registered tax agent, licensed financial adviser, or qualified lawyer. Information was current at the time of publication and may change without notice. We review and update guides periodically.
