Marketplace · Two-sided
CAC looked fine — until we split it by cohort.
This marketing & margin audit surfaced $82k in recurring annual margin in a Marketplace business — evidenced, senior-reviewed, and delivered in 7 days.
The business
A two-sided marketplace reported a healthy blended customer-acquisition cost to its board every quarter and used that reassuring number to justify a steady, growing acquisition budget. Because the blended figure sat comfortably within target, acquisition was treated as a solved problem, and the focus stayed on scaling volume rather than interrogating who exactly was being acquired.
What triggered the audit
Growth tracked to plan, yet the path to profitability kept slipping further out with each forecast. That divergence between healthy growth metrics and a receding break-even usually means an average is hiding something, so the audit broke the comforting blended CAC apart by cohort — the level at which marketplaces most often bury their worst economics.
What the audit found
Split into its component cohorts, the reassuring blended number came apart. One substantial acquisition segment was being bought at a cost far above its realistic lifetime value, so every customer from that source was underwater from the day they joined. The blend had been averaging those losses against genuinely profitable cohorts, producing a headline CAC that looked fine while masking a segment that could never pay back. Because the board only ever saw the average, the marketplace had been confidently funding its own losses, scaling a cohort that made the unit economics worse the more of it was acquired. The gap between the blended story and the cohort reality was the difference between a business that was improving and one quietly deteriorating beneath a healthy-looking metric.
What we changed
Capped spend on the loss-making cohort and reallocated it to the segments that clear CAC-to-LTV comfortably, so acquisition compounds value instead of quietly eroding it.
Switched board reporting from a single blended CAC to cohort-level CAC:LTV, so averages can no longer conceal a structurally unprofitable segment beneath a healthy headline.
Set guardrails so no cohort can be scaled beyond the point at which its own economics break down, preventing the business from funding its own losses.
Gave the growth team cohort-level targets, aligning day-to-day acquisition decisions with lifetime profitability rather than raw volume.
The result
Blended margin improved 29% by refusing to keep buying a segment that never paid back. Any marketplace board should note how it hid: a single blended CAC averaged the losses away, so the number on the slide looked healthy while profitability receded. If you report acquisition as one figure, an unprofitable cohort can scale unnoticed — the average is precisely where it hides. It takes cohort-level analysis to expose it, the resolution most dashboards don’t show. A fixed-fee audit delivers it in days, before you fund more of the loss.
From kickoff to signed-off findings: 7 days — inside our fixed 5–7 day window.
This +29% blended margin gain is ≈$82k/yr at the client’s revenue scale.