Margin Leakage

Margin leakage is the gap between the gross margin a services engagement was priced to deliver and the margin it actually produces at close, accumulating from discounting, scope absorption, write-offs, and delivery cost overruns.

It is rarely a single event. It is the cumulative result of small decisions made across the engagement lifecycle that individually appear reasonable but collectively destroy profitability.

Where margin leaks

Margin leakage has four primary sources.

Front-end discounting. The proposal price is reduced to win the deal, but delivery cost assumptions are not adjusted. The firm prices itself into a margin shortfall from day one.

Scope absorption. Work outside the original statement of work is delivered without a change order. These hours appear in cost but not in revenue.

Write-offs at invoicing. Partners reduce invoices at the point of billing, usually to avoid a client conversation. The delivery cost is already sunk.

Seniority mix drift. An engagement is priced with a junior-heavy team but delivered by seniors. The cost rises; the revenue stays flat.

Why it is hard to see

Margin leakage rarely shows up as a single line item. It surfaces only when the original engagement margin model is compared against final actuals. Most firms do not run this comparison systematically, which means leakage accumulates engagement by engagement without triggering a review.

The formula

Margin leakage (%) = Priced margin (%) - Actual margin (%) at close

Margin leakage ($) = (Priced margin % - Actual margin %) x Engagement revenue

An engagement priced at 40% gross margin that closes at 28% has leaked 12 margin points. On a $500,000 engagement, that is $60,000.

How to reduce it

• Lock the margin floor at proposal approval and require sign-off to go below it.
• Run a mid-engagement margin review at 50% of the planned timeline, not just at close.
• Require change orders for any out-of-scope work before it is delivered.
• Cap unilateral write-offs above a threshold (for example, $500 per invoice) and require a second sign-off.
• Track seniority mix weekly against the staffing plan embedded in the proposal.

The realization gap is a related measure: it captures the difference between hours worked and hours billed, which is one component of margin leakage.