Transfer pricing is one of those topics business owners assume applies only to FTSE 100 multinationals. The framework is global, the rules are extensive, and the documentation can be daunting. But the UK transfer pricing rules are written so that even small and medium-sized groups can be caught, particularly where cross-border transactions are non-trivial or where structures cross the SME exemption thresholds. Understanding when the rules bite is the first step in not being caught out.
The basic principle
UK transfer pricing rules sit in TIOPA 2010 Part 4 and apply to "provisions" between connected persons that differ from the arm's-length terms. Where related parties (typically companies under common control) transact with each other on terms that an unrelated party would not have accepted, HMRC can adjust the UK taxable profits to the arm's-length amount.
The classic example is a UK subsidiary buying goods from its overseas parent at inflated prices, reducing UK taxable profit and shifting income to a lower-tax jurisdiction. The UK rules allow HMRC to recompute the UK position at arm's-length pricing.
The SME exemption
UK transfer pricing has an SME exemption that takes most small and medium groups out of scope. An SME for these purposes follows the EU definition: fewer than 250 employees and either turnover at or below EUR 50 million or balance sheet total at or below EUR 43 million, measured on a group basis.
Even within the SME exemption, transfer pricing rules can still apply to transactions with parties in "non-qualifying territories" — broadly territories that do not have a double tax treaty with the UK containing a non-discrimination article. For most established trading partners (US, EU, Australia, Canada, Japan, India, UAE), this exception does not affect day-to-day operations.
The SME exemption is not automatic in all senses. Medium-sized enterprises (between SME and large) can still be required to apply transfer pricing if HMRC issues a transfer pricing notice. Small enterprises are largely outside the rules entirely, even on transfer pricing notice.
When the SME exemption breaks
The SME definition is measured at group level. A small UK operation that is part of a larger global group does not benefit from the SME exemption if the global group exceeds the thresholds. This catches many UK subsidiaries of US or European mid-market groups that consider themselves "small UK businesses" but are part of larger consolidated structures.
Aggregation rules treat connected enterprises as a single group for SME assessment. Partnerships and related entities under common ownership all count. Founders setting up multiple small companies under common control should be aware that the group test will count them together.
What counts as an in-scope transaction
Once outside the SME exemption, any "provision" between connected parties is potentially in scope. The provision is widely drawn: it includes the supply of goods, services, intangibles (royalties for IP), and finance (loans and guarantees). The arm's-length question applies separately to each provision.
Intra-group financing is one of the most common areas of dispute. The interest rate on a parent-to-subsidiary loan must reflect what an unrelated lender would have charged, considering the borrower's standalone creditworthiness, the loan terms, security, and currency. Below-market rates result in HMRC adjusting interest deductions upwards (where the UK is the lender) or downwards (where the UK is the borrower).
The arm's-length standard and methods
The arm's-length principle is operationalised through accepted methods: comparable uncontrolled price (CUP), resale price, cost plus, transactional net margin method (TNMM), and profit split. The selection depends on the transaction type, the availability of comparables, and the functional analysis of the parties.
For SMEs reaching the threshold, the TNMM is often the default for service and distribution transactions because it requires fewer comparables and is administratively lighter. For royalties and IP, comparable transaction analysis or profit split is more common.
Documentation expectations
From April 2023, the UK introduced explicit transfer pricing documentation requirements for large UK businesses (broadly UK members of MNE groups with consolidated turnover above EUR 750 million). The requirements are aligned with OECD BEPS Action 13: master file, local file, and Country-by-Country Report.
For mid-market groups below the EUR 750 million threshold but above the SME exemption, formal documentation is not mandated in the same way, but the burden of proof in any HMRC enquiry rests with the taxpayer. Contemporaneous documentation — functional analyses, comparables, pricing rationale — is the practical defence against penalty exposure.
Practical steps for mid-market groups
If your group has crossed (or is approaching) the SME thresholds and has cross-border related party transactions, the immediate actions are: identify all related-party transactions, classify them by type and value, perform a functional analysis of the UK entity's role, and document the pricing basis. Annual updates are sensible, and a benchmarking refresh every three to five years is conventional.
Penalties and enquiries
HMRC transfer pricing adjustments carry the standard corporation tax penalty regime: up to 30% of the additional tax for careless errors, up to 70% for deliberate, and up to 100% for deliberate and concealed. The exposure is multi-year because adjustments can go back four years (or six for carelessness, or twenty for deliberate behaviour).
How PushDigits supports cross-border SMEs
Our tax planning team reviews group structures for SME exemption status, prepares functional analyses and arm's-length pricing files where required, and coordinates with overseas advisors on bilateral consistency. Our business advisory team works with growth-stage groups on the structural questions around financing, IP location, and management services.
If your group is approaching the SME thresholds or has cross-border related-party transactions you have not formally tested, book a transfer pricing review or visit our contact page.