Fractional CFO is a term that has been stretched to mean almost anything — from an Excel tutor who moonlights for three startups, to a semi-retired public-company CFO parachuting in for fundraise cycles. Neither is wrong; neither is what a founder actually gets from a partner-led desk.
A good fractional CFO owns the calendar: monthly close, board cadence, investor reporting, 409A refresh. They own the model, the data room, and the narrative. They are accountable for the numbers they sign.
What they do not do: fill the seat of a full-time operator who is supposed to be on Slack with every cross-functional team, 40 hours a week. The fractional role is leverage; the fractional is paid for judgement, not hours.
The clearest tell we look for in the first conversation: does the founder know what the next two board meetings are about? If yes, we can help. If no, we start there — that is the diagnostic.