a finance function
that fits between rounds, not on the payroll.
Zellweger Advisory is a one-desk fractional CFO practice in Stamford. We build the models growth-stage founders take into board rooms and diligence — and we stand behind every line when the questions start.
how the practice is set up · the shape of the work
to series a
built after one too many models that fell apart under diligence
Zellweger Advisory started in a specific, familiar moment: a founder with real traction, a term sheet on the table, and a spreadsheet that couldn't answer the associate's third follow-up question. The numbers were optimistic where they should have been driver-based, and rigid where they should have flexed.
After a decade building and stress-testing Series-A models — inside operating teams and across the table during diligence — the practice was set up to do one thing well: give growth-stage founders a finance function that holds up when the room gets skeptical, without carrying a full-time CFO salary before the balance sheet can bear it.
three commitments, on the record
Each is a working rule, not a slogan — the kind of thing an investor's finance lead can check against the file we hand you.
every number traces to a driver
No hard-coded hope. Revenue, headcount, and burn tie back to assumptions you can see, argue with, and change in one cell — so when a lead pushes, the model answers instead of breaking.
you own the file, not a login
We build in live Excel or Google Sheets you keep outright — audit-ready, documented, and walked through with your team. No black-box tool you have to keep renting to read your own runway.
a fixed scope, a fixed price
Each engagement has a named deliverable and a number attached before we start. You buy an output you can hand to a board — not an open hourly meter that grows in the last week of a raise.
the person on the kickoff is the person in the board room
This is a deliberately small practice. The same advisor scopes the engagement, builds the model, and sits in on the finance conversation with your lead — through close, when it's the raise-ready scope. Nothing about your cap table gets learned twice.
Between milestones we stay in the background. When a raise, a hire wave, or a budget reset lands, the hours scale up to match. You keep CFO-grade judgment on call without keeping it on payroll.
how engagements are priced →four working habits behind a model that holds
Not a sales process — the operating rhythm of an engagement, from the first shared folder to the follow-up email after a board meeting.
we start from your actuals, not a template
The first build reads your last three months of real numbers and your cap table. The model is shaped to how your business actually earns and spends — not force-fit into someone else's SaaS assumptions.
we model the downside on purpose
Every forecast ships with the scenario a skeptical investor will run themselves — slower ramp, later close, higher burn — with the two levers that change the runway math flagged in plain language.
we write the narrative, not just the numbers
A board deck earns its place when it answers the follow-up before it's sent. Each month we pair the close with a short written read on what moved, what it means, and what decision is due.
we hand it over and teach it
At the end of a build your team gets a walkthrough of the file — where the drivers live, how to update actuals, and which cells to never touch. The goal is a model your team can run between our sessions.
bring the cap table, we'll bring the plan
A 30-minute scoping call names the right engagement and a fixed price. No obligation to proceed — just an honest read on where your numbers stand.
scope an engagement