Plain English
Instead of comparing prices, you compare profitability. Pick the simpler party — the one without unique intangibles — and check that its operating margin sits where independent companies doing similar work land. It is the workhorse method because margin data is available even when price data is not.
Technical definition
Examination of the net profit relative to an appropriate base, such as costs, sales or assets, that a taxpayer realises from a controlled transaction, compared with the net profit indicator realised in comparable uncontrolled transactions.
Why it matters
It is the most used method globally, which means most audits are arguments about TNMM inputs: tested party, profit level indicator, comparable set, and adjustments.
How it works in practice
- 01Select the tested party — the least complex party with reliable data.
- 02Choose a profit level indicator: operating margin, full cost mark-up, Berry ratio, return on assets.
- 03Build a comparable set of independent companies.
- 04Compute the multi-year range and compare to the tested party result.
- 05Adjust to a point in the range, commonly the median, if outside.
Worked example
Limited-risk distributor
A distributor reports revenue of 40m and operating profit of 0.6m, a 1.5% operating margin. The benchmark interquartile range is 2.4% to 5.1%. A year-end adjustment increasing the distributor's profit to the 3.4% median requires a credit note of roughly 0.76m from the principal, booked before year end to avoid customs and VAT complications.
Common mistakes
- Testing the entity rather than the transaction when the entity has multiple segments.
- Choosing a profit level indicator inconsistent with the functional profile.
- Making the year-end adjustment after the accounts close.
- Selecting the complex, intangible-owning party as the tested party.
Audit red flags
- Tested party outside the range in the same direction three years running.
- Berry ratio used for an entity that carries inventory.
Documentation & data
Documents to hold
- Segmented P&L reconciling to statutory accounts.
- Profit level indicator rationale.
- Year-end adjustment calculation and booking evidence.
Data you need
- Reliable cost allocation keys for segmentation.
- Comparable company data with sufficient independence screening.
Who owns this internally: Group tax with FP&A running the monitoring model.
Jurisdiction notes
- United States
- The comparable profits method is the close analogue and applies an interquartile range under the regulations.
- India
- Historically applied a tolerance band around the arithmetic mean rather than the interquartile range; rules have evolved, so check the current year.
Notes by role
CFOs & finance leaders
TNMM is why your local entities show stable, modest margins. Budget for the true-up; it is a real cash movement, not an accounting entry.
In-house tax teams
Run a quarterly monitoring model. Year-end surprises are the main source of unplanned adjustments.
Frequently asked
- Why is TNMM so common?
- Net margins are less sensitive to product differences than prices, and independent company financials are widely available in databases.
- Median or anywhere in the range?
- If your result is inside the range, no adjustment is generally needed. If outside, many authorities adjust to the median.
Sources & status
- Primary source
OECD Transfer Pricing Guidelines, Chapter II, Part III, Section B
OECD, 2022
- Our interpretation
Quarterly monitoring as leading practice
This glossary, 2026
Reference material only, not advice on a specific fact pattern. Reviewed 2026-06-30.
Careers
How this shows up in the job
If you can build and defend a TNMM segmentation in Excel, you are employable in transfer pricing.
Careers in transfer pricing