Monthly CAC (Prior Quarter)
The total sales and marketing spend recorded two months before the current month — a lagged acquisition-cost benchmark used to read spend trends against the current period.
◆ Currency
Formula
Built from
What it measures
The absolute dollar amount of sales and marketing spend booked two months ago — rep and marketer salaries, commissions, ad spend, events, content, and go-to-market tooling, the same acquisition pool that feeds CAC. It is a point-in-time copy of that prior month's spend, not a per-customer cost and not an average: it carries the value forward so this month can be read against it.
Why it matters
A single month's CAC tells you what you spent; the prior-quarter value tells you whether that spend is accelerating or decelerating. Holding a two-month-old reference next to the current month lets you spot a step-change in go-to-market investment the moment it happens, before it shows up in payback or per-logo cost. Boards use the comparison to answer one question fast: is the acquisition engine getting heavier or lighter, and is the change buying proportional growth in new logos and revenue?
How to read it
Read this as a comparison anchor, never as a target. Put it beside the current month's CAC and look at the direction. If current CAC is climbing while the prior-quarter figure was flat, spend is accelerating — confirm new logos and New ARR are accelerating with it. If both are falling, you are pulling back; check that pipeline and bookings can survive the cut. The gap between the two is the signal — a large swing in either direction is a prompt to decompose the spend (headcount, campaigns, one-time events) before drawing a conclusion.
What good looks like
Good
Spend stable or moderately rising over the two-month lag, matched by growing new logos, New ARR, and net revenue retention — you are buying proportional growth.
Watch
Spend swinging sharply between the lagged month and the current month with no clear driver; decompose headcount, campaigns, and one-time costs before acting.
Bad
Spend climbing month over month while new logos and expansion stay flat — acquisition is getting heavier with nothing to show for it.
Watch-outs
- Treating it as a budget target. This is a historical reference, not an allocation. Last quarter's spend tells you what happened, not what this month should be capped at — a company growing into a bigger market should often spend more, not match the lag.
- Reading it as acquisition efficiency. A high prior-quarter figure does not mean customers are expensive to acquire. Efficiency is spend divided by the customers it produced (CACU) or recovered through margin (CAC payback) — the raw pool says nothing about either on its own.
- Ignoring composition swings. A spike two months ago could be a one-time event — a conference, a hiring wave, an annual tooling renewal — not a sustained shift. Always trace the prior-month total back to its drivers before comparing.
- Misattributing the lag. The two-month offset compares spend periods, not spend to the customers it produced. A campaign in the prior month often closes deals this month or next, so never pair this figure with current-month logos to back into a per-customer cost.
Worked example
Hypothetical
It is May. In March you spent $180K on sales and marketing — $80K on rep and marketer salaries and commissions, $70K on campaigns and events, and $30K on go-to-market tooling. The prior-quarter CAC for May is that March figure, $180K. May's actual spend is $210K, so spend has accelerated $30K (about 17%) over the two-month lag — a prompt to confirm new logos and New ARR rose in step.
Variants & windows
The same metric re-expressed by a mechanical transform — a trailing window, a growth rate, a per-unit scaling, or a book/segment cut. Each is computed from Monthly CAC (Prior Quarter) above.
- T3M CAC (Prior Qtr) Trailing 3-month