Your biggest client might be your least profitable. And it won’t show up in your project data.
Project profitability tells you which work is making money, but profit leaks don’t live in just one place.
For ‘the big client’ the projects might all show up as ‘green’. But the proposals took three rounds. The “quick questions” eat two hours a week. The invoice sits unpaid for 90 days. The account management overhead is double anyone else’s.
That’s cost to serve, and most agencies don’t track it.
Here’s the three-layer view I use:
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Delivery profitability (per project) Revenue vs the real operational cost of delivery - briefings, revisions, PM overhead, rework. This is where most people start. Clearly sensible.
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Cost to serve (per client) The work around the work: proposals, meetings, admin, internal conversations, invoice chasing, “quick questions.” Your biggest client can be your least profitable. Often the leak isn’t the work - it’s the work you do to keep the work moving.
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Operations + capacity (how the business runs) Not “who’s under-performing.” What in the system is eating capacity and pushing up your true cost of delivery: unclear ownership, decision paths that escalate, visibility that arrives after the month is over. Senior time getting pulled into low-value work. To AI or not to AI? If your best people are the escalation path, margin will always feel “mysterious.”
Each layer tells you the size of the problem in a different area, and each one points to a different set of fixes.
If you only look at projects, you end up fixing the wrong thing: tightening scopes when the real drag is proposal time, repricing when the real issue is cost to serve, hiring when the real leak is handoffs and rework.
Which layer is the black box in your business right now?