Contract Manufacturer Transfer Pricing: Cost Plus, TNMM, and Audit Issues (2026)Contract Manufacturer Transfer Pricing: Cost Plus, TNMM, and Audit Issues (2026)
How to price contract and toll manufacturing arrangements: tested party selection, cost plus vs TNMM, cost-base design, capacity utilization, inventory and warranty risk, benchmarking, documentation, and audit issues.
Borys UlanenkoCEO, ArmsLength AI
18min read
Contents↓
Contents
TL;DR key takeaways
A contract manufacturer is usually the routine tested party when it produces to a principal's specifications, does not own product IP, and has limited inventory, market, and warranty risk.
Contract, toll, and full-fledged manufacturers should not be benchmarked together. Ownership of materials, inventory risk, production planning, warranty exposure, and IP control change the pricing answer.
Traditional cost plus can be defensible when reliable gross mark-up data exists. TNMM with Net Cost Plus is often more practical when gross-level cost classification is noisy.
Cost-base policy matters as much as the mark-up. Pass-through materials, idle capacity, abnormal scrap, start-up losses, tooling, and warranty costs need explicit treatment.
Audit files should tie the contract, actual conduct, ERP cost mapping, benchmarking search, year-end true-up, and capacity-utilization analysis into one coherent manufacturing story.
How to price contract R&D arrangements: distinguishing routine research services from entrepreneurial IP development, DEMPE and risk control, cost plus vs TNMM, cost-base and mark-up issues, tax/accounting caveats, documentation, audit issues, and examples.
Cost plus and TNMM can both use costs as a reference point, but they are not the same transfer pricing method. This guide explains gross mark-up vs net cost plus, when each method fits, examples, audit risks, and documentation points.
A practical guide to the Comparable Uncontrolled Price method: internal vs external CUPs, comparability thresholds, commodity pricing, adjustments, worked examples, common mistakes, and documentation points.
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Quick answer: how should contract manufacturing be priced?
A contract manufacturer usually earns a routine manufacturing return when it produces goods to an affiliate's specifications and the principal controls product IP, market strategy, and material entrepreneurial risks. The usual tested-party answer is the manufacturer. The usual profit indicator is a cost-based return, either a traditional cost plus gross mark-up or TNMM with Net Cost Plus.
That answer depends on facts. A toll manufacturer that never owns materials normally earns a return on conversion activities. A contract manufacturer that takes title to inventory may need compensation for working capital and operational risk. A full-fledged manufacturer that controls product design, procurement, production strategy, inventory, warranty, and market risk usually cannot be treated as routine.
The label in the intercompany agreement is only a starting point. The transfer pricing result follows the actual functions, assets, and risks.
Profile
Materials and inventory
Decision rights
Typical return
Toll manufacturer
Principal owns raw materials and finished goods
Converts materials under principal instructions
Conversion cost plus routine return
Contract manufacturer
Manufacturer may take title, but output is usually committed to the principal
Operates plant and executes production plan
Cost plus or TNMM return on manufacturing costs
Full-fledged manufacturer
Owns materials and finished goods, sells into market
Controls procurement, production, product, warranty, and market choices
Entrepreneurial return, often not a routine tested party
Toll manufacturing
A toll manufacturer usually provides capacity, labor, production know-how, and plant operations. It does not buy raw materials for its own account and does not own the finished goods. Pricing normally starts with conversion costs: direct labor, production overhead, quality control, and plant support costs tied to the tolling activity.
The main cost-base question is whether any third-party charges are true pass-throughs. If the toller coordinates logistics, subcontracting, or testing and adds value, a zero mark-up pass-through may be too thin. If it merely pays an invoice as agent for the principal, including that amount in the mark-up base can overstate the toller's return.
Contract manufacturing
A contract manufacturer may take title to materials and finished goods, but the principal usually commits to purchase output, owns product intangibles, sets specifications, and bears demand risk. This profile is common in electronics, medical devices, automotive components, industrial goods, and consumer products.
The manufacturer is normally the tested party if it does not own unique intangibles and comparable independent manufacturers can be found. The benchmark should match the actual risk package. A manufacturer with purchase commitments and principal-funded tooling should not be compared to independent producers that carry open-market demand risk.
Full-fledged manufacturing
A full-fledged manufacturer controls more of the value chain. It may design products, choose suppliers, own process or product IP, take market risk, manage inventory for its own account, handle warranty exposure, and sell to independent customers.
Treating this entity as a routine cost-plus manufacturer creates audit risk. If the manufacturer controls unique production processes, valuable know-how, or product decisions, a one-sided routine return may strip profit away from the entity that actually creates value.
Tested party selection
Under OECD guidance, the tested party for one-sided methods is generally the party to which the method can be applied most reliably, often the less complex party. Contract manufacturers often fit that profile because independent comparables exist for routine production activities. See and .
Use a tested-party matrix before selecting the method:
Factor
Routine manufacturer answer
Warning sign
Product IP
Principal owns and controls it
Manufacturer develops product technology
Production process
Standard process execution
Manufacturer owns unique process know-how
Inventory risk
Principal commits to buy output or covers obsolete stock
Manufacturer sells output into uncertain demand
Warranty risk
Principal bears product warranty
Manufacturer bears field failure costs
Capacity risk
Principal commits volumes or compensates underutilization
Manufacturer absorbs idle plant cost
Procurement
Principal approves suppliers and specs
Manufacturer controls strategic sourcing
Comparables
Independent contract manufacturers exist
Only full-risk manufacturers are available
Warning
If the manufacturer controls the risks that drive profit, do not force a routine tested-party answer. Revisit the accurate delineation of the transaction before selecting TNMM or cost plus.
Cost plus vs TNMM for contract manufacturers
The method choice turns on data reliability, not preference.
Traditional cost plus
The cost plus method starts with manufacturing costs and adds an arm's length gross mark-up. OECD Chapter II describes cost plus as useful for semi-finished goods, long-term buy-and-supply arrangements, and services. HMRC's cost plus manual also cautions that a cost plus label does not make an arrangement arm's length by itself.
Cost plus is strongest when:
the manufacturer has internal comparable uncontrolled manufacturing arrangements
reliable gross mark-ups can be extracted from comparable companies or contracts
cost classification between the tested party and comparables is consistent
the manufacturer performs routine production rather than full entrepreneurial manufacturing
TNMM with Net Cost Plus
TNMM tests operating profit against an appropriate base. For manufacturers, the usual PLI is Net Cost Plus, calculated as operating profit over total costs. See Net Cost Plus for the formula.
TNMM is often more practical when:
external data is available only at operating-profit level
comparables classify depreciation, engineering, warranty, freight, or plant overhead differently
the tested party has a stable routine profile
gross margin differences cannot be reliably adjusted
Issue
Cost plus
TNMM with Net Cost Plus
Profit level
Gross mark-up
Operating profit mark-up
Cost base
Usually production or service costs
Usually total operating costs
Data source
Internal contracts, gross-level public data where available
Commercial comparable-company databases
Main weakness
Cost classification sensitivity
Can mask product and functional differences
Best use
Clear gross comparability
Routine manufacturer with reliable net comparables
Cost-base issues that decide the answer
The mark-up often gets attention, but audits usually move to the denominator: which costs were marked up, excluded, normalized, or passed through.
Direct materials
For contract manufacturers that buy materials, raw materials may be part of the cost base if the manufacturer performs procurement, quality, storage, and inventory functions. For toll manufacturers, principal-owned materials are usually outside the toller's cost base.
Pass-through costs
A pass-through cost should have a clear agency or no-value-add fact pattern. If the manufacturer coordinates vendors, controls quality, bears delay risk, or manages the supplier relationship, a tax authority may expect compensation for that activity.
Tooling and engineering
Tooling can sit in several places: owned by the principal, owned by the manufacturer, reimbursed at cost, capitalized, leased, or embedded in unit price. The documentation should show who funded the tooling, who controls it, who bears obsolescence risk, and whether depreciation sits in the marked-up base.
Start-up and abnormal costs
Start-up costs, abnormal scrap, product launch inefficiencies, flood or fire losses, and one-off restructuring costs should be analyzed separately. Independent manufacturers may not pass all abnormal costs to customers. If the principal caused the cost or agreed to absorb it, the contract and conduct should support that treatment.
Capacity utilization
Idle capacity can distort a cost-plus model. A manufacturer with a 50% utilized plant may show high unit costs, and marking up all idle costs may overcharge the principal unless independent parties would do the same.
Document:
normal capacity assumptions
actual utilization by month or quarter
whether underutilization was caused by principal forecasts, market demand, plant inefficiency, or launch timing
how comparables' capacity profiles were considered
whether a capacity adjustment or separate compensation is more reliable than hiding the issue in the mark-up
Inventory, warranty, and production risk
Risk allocation should follow both contracts and conduct. OECD Chapter I asks who assumes risk contractually, who controls it, and who has financial capacity to bear it.
Inventory risk
A contract manufacturer may hold inventory on its balance sheet without bearing full inventory risk. Purchase commitments, buy-back clauses, principal-approved safety stock, and reimbursement for obsolete materials can shift the economic risk back to the principal.
Audit files should reconcile:
title transfer point
responsibility for obsolete and slow-moving inventory
raw material purchase approvals
finished-goods purchase commitments
insurance and storage obligations
Warranty risk
Warranty clauses are often too thin. Separate manufacturing-defect risk from product-design risk:
Routine manufacturers still bear operating risk. They need to manage labor, yields, quality, and plant execution. The question is whether those risks are capped or entrepreneurial. A guaranteed margin with no accountability for poor quality may not match independent behavior. A manufacturer that absorbs all production losses may need a higher return or a different profile.
Benchmarking approach
Start with the accurately delineated profile, then search for comparables that match it.
Search design
For TNMM benchmarking, a typical search screens for independent manufacturers by industry code, geography, ownership independence, financial data availability, and functional profile. The manual screening matters. Many "manufacturers" in databases are full-risk producers with brands, product R&D, or third-party sales exposure.
For cost plus, internal comparables should be considered first. If the same factory manufactures similar products for unrelated customers, the internal mark-up can be powerful evidence if volumes, specs, risks, assets, and terms are comparable.
PLI selection
Net Cost Plus is common for routine contract manufacturers because costs drive the value contribution. Operating margin may be less intuitive for captive manufacturing where revenue is an intercompany price rather than a market sales measure. ROA or ROOA may be relevant for asset-intensive manufacturing if plant and equipment drive returns.
The year-end true-up should be tied to the tested PLI and the contractual pricing policy. A policy that says "5% mark-up" but true-ups to a TNMM interquartile range should explain whether the legal policy is a gross cost plus method, a net TNMM policy, or a price-setting rule tested under TNMM.
Documentation package
A good contract manufacturer file should include:
Document
What it should prove
Intercompany manufacturing agreement
Scope, title transfer, purchase commitments, risk allocation, pricing, true-up
Functional analysis
Who controls production, procurement, inventory, warranty, capacity, and IP
Cost-base mapping
ERP accounts included, excluded, and treated as pass-through
Benchmarking study
Search strategy, screens, manual rejections, selected PLI, range
Capacity analysis
Normal vs actual capacity and treatment of idle cost
Actual tested-party result, true-up, invoice support, local accounting entry
Tip
Match the contract to operating evidence. If the agreement says the principal bears inventory risk, the file should include purchase forecasts, inventory write-off reimbursements, or buy-back mechanics. A clause without conduct rarely resolves an audit.
Common audit issues
Tax authorities usually focus on a short list of pressure points:
The manufacturer is called "limited risk" but absorbs idle capacity, scrap, and warranty losses.
The cost base includes principal-owned materials or other pass-throughs without analysis.
The company uses full-fledged branded manufacturers as comparables.
The agreement allocates risk to the principal, but local management controls the risk in practice.
The year-end true-up is booked after local deadlines or without legal support.
The manufacturer performs process R&D or product engineering without separate compensation.
Customs values, inventory accounting, and income-tax transfer prices do not reconcile.
The IRS transfer pricing materials emphasize fact development and whether intercompany results match economic reality. The same practical point applies outside the United States: labels, ranges, and contracts need to line up with plant-level facts.
Worked example
Facts: HungaryCo manufactures industrial sensors for its Swiss principal. The Swiss principal owns product designs, approves suppliers, commits to buy all output, and bears market risk. HungaryCo buys materials in its own name but is reimbursed for obsolete inventory caused by forecast changes. HungaryCo owns plant equipment and manages production labor.
Method selection: HungaryCo is the tested party. No reliable internal gross mark-up data exists. External gross margins are inconsistent because comparables classify engineering and plant overhead differently. TNMM with Net Cost Plus is selected.
Item
Amount
Revenue from principal
EUR 54,000,000
Raw materials
EUR 32,000,000
Direct labor
EUR 7,000,000
Manufacturing overhead
EUR 9,000,000
Operating expenses
EUR 3,000,000
Total costs
EUR 51,000,000
Operating profit
EUR 3,000,000
Net Cost Plus
5.88%
The benchmarking study finds an interquartile range of 4.2% to 7.1% NCP for independent contract manufacturers. HungaryCo's 5.88% result falls within the range.
Capacity point: During Q2, principal forecast reductions created idle time. The principal reimbursed documented idle labor and fixed overhead under the agreement. The file includes forecast changes, plant utilization reports, and the reimbursement calculation. Those facts support treating the idle-cost recovery separately from HungaryCo's routine NCP.
Frequently asked questions
Is a contract manufacturer always a tested party?
Usually, but not always. The manufacturer is a strong tested-party candidate when it performs routine production, lacks unique intangibles, and reliable comparables exist. If it controls product design, process IP, warranty risk, or market decisions, the routine tested-party assumption may fail.
Should contract manufacturers use cost plus or TNMM?
Use cost plus when reliable gross mark-up comparables exist and cost classifications are consistent. Use TNMM with Net Cost Plus when net-margin data is more reliable than gross mark-ups. The method should follow the facts and available data.
Should raw materials be included in the mark-up base?
It depends on who owns and controls the material risk. Raw materials are often in the cost base for contract manufacturers that buy, store, and manage materials. Principal-owned materials in a toll model are often excluded.
How should idle capacity be handled?
Identify the cause. Idle capacity from principal forecast changes may justify separate compensation. Idle capacity from local inefficiency may sit with the manufacturer. Normal capacity, actual utilization, and contract terms should be documented.
What is the biggest audit risk?
The main risk is inconsistency: a "limited-risk" manufacturer that actually bears full production losses, warranty exposure, obsolete inventory, or market risk. That mismatch can undermine both the tested-party selection and the benchmark.
Borys UlanenkoCEO, ArmsLength AI
