by Trey Pruitt
Polyphony (1932) by Paul Klee, public domain via Wikimedia Commons.
When a subscription CEO decides to get outside help with the numbers, the hard part isn't finding someone — it's knowing what kind of help you're actually buying. The labels blur together. A generalist fractional CFO, an FP&A platform, a strategic finance advisor, a cohort analysis: they sound like they overlap, and the differences only become clear once you're already six months and a retainer into the wrong one.
I work as a fractional CFO, but not a generalist one — the depth goes into subscription forecasting. So here's plainly what cohort forecasting and unit economics is, what it isn't, and why the distinction matters when you're deciding what to hire.
Cohort forecasting and unit economics is a way of running planning in a subscription business that connects three things most companies leave disconnected:
The cohort math underneath your revenue. Your customers acquired in 2024 don't behave like your customers acquired in 2022. Their retention curves are different, their expansion patterns are different, the cost to acquire them was different. Treating them as one homogeneous block — which most planning approaches do — washes out the signal that actually predicts where the business is going.
The marketing spend → LTV → cash spine. Marketing spend creates customers. Each cohort of customers is worth some lifetime value — the retention and revenue you'll actually collect from them over time. That LTV is what eventually becomes cash. Most subscription companies model one or two of these links in isolation — a revenue forecast here, a hiring plan there, a board deck with the cash number sourced from somewhere. The output is a plan that doesn't reconcile to itself.
The decision rhythm of the people actually running the business. A plan that produces a beautiful three-statement model nobody opens between board meetings is a deliverable, not a planning system. The whole point is to be useful in the weeks between board meetings — when you're deciding whether to lean into a channel, whether you can afford the senior hire, whether the missed quarter is a blip or a trend.
The output isn't a forecast file. It's a working planning system, configured to your data, refreshed each cycle, with judgment applied where the math runs out — and decision-grade outputs that hold up under board scrutiny: marketing-spend payback, lifetime value, revenue retention, EBITDA, cash impact, runway, plan-vs-actuals. This is the specialty I bring into the fractional-CFO seat: not everything a finance function touches, but the forecasting a subscription business actually turns on.
It isn't generalist fractional CFO work. A generalist fractional CFO spreads across the whole finance function — close, treasury, audit, banking, fundraising mechanics, contracts — doing each of them adequately. I work as a fractional CFO too, but the depth is concentrated in one place: subscription forecasting at a level a generalist can't reach, on software built for exactly this and already running rather than assembled from scratch for each engagement. Same seat, different center of gravity. Where an engagement needs the broader CFO scope, that can sit alongside — but the reason to hire me is the depth, not the breadth.
It isn't an FP&A platform. Mosaic, Pigment, Cube, Anaplan — these are configurable tools that, properly implemented, give your team a place to build and maintain a plan. They're real software with real value. But the value depends entirely on the quality of the model that gets built inside them, and they're designed for in-house FP&A teams to do the building. Cohort forecasting and unit economics is the modeling work, productized — built on software designed specifically for subscription dynamics rather than general-purpose finance configuration, and run by the person who reads the output.
It isn't generic strategic finance. "Strategic finance" as a category sits adjacent to FP&A and has come to mean "the part of finance that doesn't close the books." That's broader than what I go deep on. Cohort forecasting and unit economics is specifically forecasting — driver models, scenario stacks, cohort sensitivity, cash projection — for businesses where recurring revenue, retention dynamics, and acquisition economics are the load-bearing parts of the model.
The names matter because they shape what you expect to get.
If you hire a generalist fractional CFO, you expect them to own everything finance-y. They probably will — thinly — because no one person can credibly own the whole finance stack at depth, so you end up with several things done adequately and the forecasting no deeper than the rest.
If you implement an FP&A platform, you expect the software to solve the planning problem. It doesn't — it gives you a place to solve it, and the quality of the plan depends on who configures it and maintains it.
If you hire me as your fractional CFO, you should expect the opposite trade: a cohort-driven model built specifically for your business, configured to your data and your decision rhythm, run each cycle with judgment applied, producing plan-vs-actuals and scenario work the board can rely on. Narrower center of gravity, deeper work — a fractional CFO whose specialty is the forecasting your business actually runs on.
CEOs of $5M+ DTC, mobile app, or PLG SaaS subscription businesses, where cohort dynamics are real enough to model. The $5M floor exists because below that, the data is usually too thin to do the cohort work justice. There's no ceiling.
The shape of the engagement: a discovery call to figure out whether this is the right fit, then — if both sides want to keep going — a setup phase that builds the planning system, followed by a monthly retainer where I run it with you as your fractional CFO.
If you're a subscription CEO and you've read this far, the next step is a discovery call. Book one here and tell me what you're trying to plan against.
