Comparable Profits Method (CPM): US Rules, PLIs and Practice

The comparable profits method (CPM) compares the profits of the controlled party in the transaction with the profits of a comparable independent party in a comparable transaction. It is one-sided — only the tested party’s profitability is examined — and it is the method US Section 1.482-5 was written around. In India the method is listed in Rule 10B, but TNMM has taken its practical place; CPM in India is mostly a shadow of the US method that survives in files written to a US template.

CPM under Section 1.482-5

The regulation fixes three disciplines:

1. One-sided testing. The comparison is made with the party whose intangibles and functions are the least complex in the transaction — the routine party, not the valuable one. The method prices the routine contribution by referencing what an independent party earns for it.
2. A PLI, not a price. CPM does not compare prices. It compares a profitability indicator of the controlled party with the same indicator of comparable independent parties, and adjusts for differences that materially affect the PLI.
3. Transaction-comparable data. The comparables are independent transactions of the same or similar kind — a contract manufacturer’s comparable is an independent contract manufacturer running a comparable contract, not just any company in the industry.

The six regulatory PLIs

Section 1.482-5(b)(3) lists the indicators the method may use:

PLI	Formula	Typical use
Gross margin	(resale price − purchase cost) ÷ resale price	Resellers, distributors
Net profit margin	Net profit ÷ revenue	General routine service providers
Cost-based mark-up	Gross profit ÷ operating cost	Contract manufacturers, service providers
Selling price-to-value-added	Sales price ÷ (sales price − COGS)	Trading operations
Inventory mark-up	Gross profit ÷ average inventory cost	Inventory-intensive resellers
Other reasonable indicator	Fact-specific	Where none of the above isolates the routine return

The list is a menu, not a ranking: the choice follows the tested party’s economics, for the same reason a PLI is chosen under TNMM — it must isolate the routine contribution and be measurable from reliable data.

CPM vs TNMM: the one structural difference

CPM and TNMM are cousins that split on a single point: what is compared with what.

• CPM compares the controlled party’s PLI with the PLI of independent parties who did the same kind of transaction. The comparables are transaction-based.
• TNMM compares the tested party’s PLI with the same PLI computed across a pool of comparable companies. The comparables are company-based, and the range (IQR) is built from the pool’s distribution.

In practice TNMM is the more robust machine: a company pool is easier to assemble from public filings and commercial databases, and the IQR absorbs single-company noise. CPM’s transaction comparables are cleaner in theory but harder to source — independent parties running the same contract with disclosed, same-year, same-PLI data is a thin set for most fact patterns.

CPM in Indian practice

Rule 10B(1) of the Income-tax Rules lists the methods: comparable uncontrolled price, resale price, cost plus, uncontrolled commodity price, TNMM, profit split, and any other method as prescribed. CPM as a named method does not appear in the list — the one-sided profit comparison it performs is what TNMM (a net PLI tested against a comparable pool) and the cost plus method (a mark-up on a defined cost base) do for Indian files.

So in an Indian file:

• Where a US file would say “CPM with a cost-based mark-up PLI”, the Indian file says cost plus (mark-up on a defined cost base) or TNMM on OP/OC (mark-up tested against a comparable pool).
• Where a US file would say “CPM with a gross margin PLI”, the Indian file says RPM / gross margin method.
• A TPO examination rarely entertains “CPM” as a label — the question is always which Rule 10B method, which PLI, and which pool.

Worked example: contract manufacturer (US-style CPM)

A contract manufacturer in the US performs a defined assembly operation for its parent. The IRS selects the manufacturer as the tested party (least complex intangibles) and tests with a cost-based mark-up:

Item	Controlled	Comparable A	Comparable B	Comparable C
Contract revenue	$10,000	$12,000	$9,500	$14,000
Operating cost	$9,200	$10,800	$8,500	$12,400
Cost-based mark-up	8.7%	9.5%	10.4%	12.1%

The comparable range (after the same operating-cost definition) spans 9.5%–12.1% with a median of 10.4%. The controlled mark-up of 8.7% sits below the range; the arm’s length position is at the range, implying additional income of roughly $170 on the $10,000 contract. The file’s job is to show why the comparable set is wrong (asset intensity, capacity utilization, contract risk) — not to argue the arithmetic.

Documentation points

• State the tested-party choice and the least-complex-intangibles reasoning.
• Show the operating-cost definition line by line — the PLI is only as good as its cost base, and a cost base that includes or excludes a material item (subcontracting, R&D overhead, intercompany fees) changes the mark-up.
• Keep the adjustment log: every comparability difference adjusted, with the amount; every difference left in, with the reason it is immaterial.
• If the file is Indian, name the Rule 10B method and PLI — do not carry the US label across.

See also

• CPM vs TNMM compared
• TNMM: the complete guide
• How to choose a method