Key takeaways
- Aggregate gross margin hides the customers and jobs that are destroying the average.
- Build a customer-level margin analysis before a buyer does it during diligence.
- Job costing reveals the work that is profitable and the work that only feels profitable.
- Reprice or exit the lowest-margin customers before a sale, while the decision is yours.
- Margin by customer is the first place a PE buyer looks after the headline EBITDA.
Revenue ≠ profit
The first principle of customer-level economics
Top 20% of customers
Often generate 80%+ of actual margin
Bottom 20% of customers
Often generate negative contribution in full-cost models
Job costing
The discipline that makes customer economics visible
McKinsey's pricing research consistently finds that the top 20% of customers by contribution margin generate 80–90% of a service business's actual profit, while the bottom 20% of customers consume 5–15% of gross margin, creating a 25–35% swing in profitability that is invisible in blended P&L reporting.
In PE-acquired service businesses, the Day 1 customer margin analysis conducted by operating teams finds that 1 in 3 large-revenue accounts (top 5 by revenue) is in the bottom half of the business by contribution margin, a finding that surprises management teams who tracked revenue but not full-cost profitability.
Businesses that systematically repriced or exited bottom-quartile accounts before a sale process achieved average gross margin improvements of 3–6 percentage points over 12–18 months, translating directly into EBITDA expansion at a 1:1 ratio (Bain Customer Profitability Research 2024).
Revenue is the metric most middle market founders know best, which customers are biggest, how revenue has grown, where the pipeline sits. Gross margin by customer is the metric PE buyers model in the first week of ownership. The gap between the two is where the most common margin surprise in post-close operations lives.
A $20M revenue business with 18% EBITDA margin is not a business where every customer generates 18% contribution. In most middle market service businesses, the actual distribution looks dramatically more skewed: a small cluster of accounts generates strong margins, a larger group generates acceptable margins, and a meaningful tail generates margins near zero or below when labor, overhead, and service costs are fully allocated.
Why most businesses do not know their customer-level economics
Most middle market accounting systems are configured to track revenue, direct costs, and overhead at a company level. They are not configured to allocate direct labor, materials, and indirect overhead to individual customers or jobs. The result: the P&L shows a blended margin that obscures the customer-level distribution.
The businesses that do have customer-level economics, through job costing systems, activity-based costing, or manual allocation, routinely discover that their mental model of customer profitability is wrong. The largest customers are not always the most profitable. Long-tenure customers are not always the most profitable. High-volume accounts that required significant service customization are often the least profitable after full cost allocation.
A $17M mechanical services business had 14 commercial accounts representing 60% of revenue. The owner's mental model ranked them by revenue size and relationship tenure. When a proper job costing analysis was run for the first time, allocating direct labor hours, materials, and a reasonable equipment overhead rate to each job, three of the top five revenue accounts were in the bottom quartile for contribution margin. One was generating a negative contribution after overhead allocation. None of this was visible in the blended P&L.
The margin illusion compounds when businesses price new work based on blended margins rather than job-level economics. A business that prices new contracts to achieve a 35% gross margin in aggregate may be systematically underpricing complex, high-labor jobs and overpricing simple, high-volume ones, and making the margin distribution worse with every new contract signed.
How to build a basic customer-level margin analysis
Customer Margin Analysis, Build Sequence
Step 1: Export job/invoice-level data
Pull 24 months of transaction data with customer, revenue, direct materials cost, and direct labor hours per job or invoice
Step 2: Assign a labor cost rate
Apply a fully-loaded labor rate (wages + benefits + workers' comp) per hour to convert labor hours to direct labor cost
Step 3: Allocate overhead
Choose a simple allocation basis, direct labor hours or revenue percentage, and allocate operating overhead (equipment, facilities, supervision) to each job
Step 4: Calculate contribution margin
Revenue minus direct materials, direct labor, and allocated overhead per job; aggregate to customer level
Step 5: Sort and segment
Rank customers by contribution margin percentage and dollar value; identify the top quartile, middle two quartiles, and bottom quartile
Step 6: Identify the actions
For bottom-quartile accounts: reprice, re-scope, or exit. For top-quartile accounts: protect, deepen, and replicate.
The M&A connection
PE buyers run this analysis in the first 30–60 days of ownership. Sellers who have already done it, and can present customer-level profitability data in the management presentation or data room, are presenting a qualitatively different level of management sophistication than sellers who present only consolidated P&L data.
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More practically, sellers who run the analysis 18–24 months before a process can address the bottom-quartile accounts before valuation is set. Exiting or repricing low-margin accounts improves the blended EBITDA margin, which directly improves the purchase price at a fixed multiple. A service business that improves its gross margin from 34% to 38% through customer portfolio rationalization adds meaningful EBITDA, and that EBITDA is the basis of the valuation.
Frequently asked questions
Why do large customers sometimes generate the worst margins?
Large customers often negotiate the deepest discounts, require the most service customization, and generate the most overhead consumption per dollar of revenue, while the revenue scale creates a false impression of profitability. The businesses where this is most pronounced are those that grew large accounts through competitive pricing without ever building a formal allocation of their full service cost.
How does customer margin analysis differ from the standard P&L?
The standard P&L shows blended company-level margins. Customer margin analysis allocates direct costs (labor, materials) and overhead to individual customers or jobs, revealing the contribution margin at a granular level. Most businesses discover a much wider distribution than their blended margins suggest, with a small number of highly profitable accounts and a meaningful tail of near-zero or negative-margin accounts.
Work with Glacier Lake Partners
Request a Margin Analysis and Profitability Review
Most useful when preparing for a transaction or when EBITDA is growing slower than revenue.
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