Most UK SMEs have a version of the same pattern in their product or service mix: roughly a third of lines produce most of the profit, a third produce modest profit, and a third are either marginal or actively loss-making once all costs are properly allocated.
Most owners do not know which third is which. They assume 'the business is profitable overall' — which is technically true — while subsidising one set of products or services with the profit from another. Identifying the drag-lines is one of the highest-return hours of commercial work an SME owner can do.
Most UK SMEs make roughly 70% of their profit from the top 25% of lines (A lines), 20% from the next 40% (B lines), and 10% from the bottom 40% (C lines) — with a handful often loss-making on a contribution basis. Run an ABC analysis by contribution margin at least annually: reprice the marginal, retire the loss-makers, and protect the A lines.
Start with contribution margin per line, not revenue
Revenue rankings lie. A £200k line at 8% contribution margin contributes less than a £80k line at 25%. Sort your products or services by contribution margin — net revenue minus direct variable costs — not by revenue.
Contribution margin means everything that varies with the unit sold: supplier cost, freight, packaging, fulfilment, payment fees, direct labour. It does not include rent, admin salary, or other fixed overheads. It is the bar that each line must clear to deserve space in the business.
The ABC analysis: your first commercial X-ray
Take your product or service list. Sort by contribution margin contribution (margin £ × volume), highest to lowest. Calculate cumulative contribution as a percentage of total.
- A lines: contribute the first 70% of total profit. Usually 15-25% of your lines. Protect these with pricing discipline, stock availability, and focused marketing.
- B lines: contribute the next 20% of profit. Usually the next 30-40% of your lines. Maintain, review annually, look for mix uplift.
- C lines: contribute the last 10% of profit. Usually 40-55% of your lines. Candidates for pricing review, repositioning, or retirement.
The 'long tail' of C lines is where most hidden profit drag lives. Not because each one loses money individually — but because together they consume disproportionate operational attention for disproportionately little contribution.
Find the outright loss-makers
Inside the C tail, there are usually a handful of lines that are actively loss-making on a contribution basis — meaning the direct variable cost is higher than the net revenue. Every sale of these lines makes the business poorer.
How to find them:
- Pull net revenue per unit (after discounts, fees, payment processing, marketplace commission)
- Pull fully-loaded variable cost per unit (supplier + freight + packaging + fulfilment)
- Calculate contribution — if negative, the line is actively destructive
- Calculate returns-adjusted contribution — for product businesses, add back the cost of the typical return rate. Some lines are positive on average but negative once returns are properly costed.
Common causes of product-level profit drag
Nine times out of ten, profit-dragging lines have one of these causes:
1. The line was priced in 2022 and costs have risen since.
A staple product at a sticky price point. Supplier cost is up 12-15%. The line is still selling but contribution has collapsed.
2. The line carries a returns rate nobody tracks.
Average returns in UK ecommerce run 6-8%. Certain categories (apparel, footwear, bulky furniture) run 20-35%. If a line has a returns rate 2x your average, its true contribution is often negative.
3. The line is being sold through a high-fee channel.
A product that makes 25% direct margin can make 3% on Amazon after FBA fees and commission. If your Amazon volume on the line is high, the real blended margin may be unprofitable.
4. The line has hidden service cost.
Products that generate frequent support queries, returns, or warranty claims carry cost-to-serve that most SME accounts do not allocate. If one product generates 25% of your customer service workload and 5% of revenue, it is a hidden drag.
5. The line is strategic but the strategy has changed.
A line kept 'for the range' or 'because one big customer wants it' — but the customer left two years ago, and nobody re-evaluated. Review quarterly.
What to do with each category
Reprice
A line that has slipped to marginal contribution usually recovers with a 5-10% price rise. Customer resistance is typically lower than you expect, because the customer is not benchmarking every price against last year's.
Reposition
Same physical product, different story. A commodity product at a commodity price becomes a premium product at a premium price with better positioning, bundling, or service wrap. Works particularly well in B2B.
Retire
Some lines should just go. The test: if you stopped selling this tomorrow, would any customers leave? If the answer is 'no, or only customers we don't want anyway' — the line is draining operational attention for no strategic benefit.
Replace
If the category is strategically important but the specific line does not work, replace the SKU/service within the same category with one that has better margin economics. Customers stay; profit improves.
How often to run this analysis
For stable businesses — annually. For businesses with frequent new product launches or changing cost base — quarterly. After any major cost input change (supplier, freight, fulfilment, payment provider) — immediately, at least for affected lines.
The analysis itself is typically 2-4 hours with a spreadsheet and your sales data. It is the single highest-return use of commercial analysis time in most UK SMEs.
Common questions
See exactly which products or services are holding you back
The LumixAI Portfolio Analyser classifies every line by contribution margin — A, B, C — and identifies the specific SKUs and services that are draining your margin.
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