Both historical and recent court decisions underscore that arm’s-length interest rates in intra-group financing must be supported by accurate delineation, robust credit risk analysis, and observable market evidence, rather than by purely mechanical benchmarking exercises.
To explore these developments, Deloitte Luxembourg has launched a dedicated series of articles examining landmark judicial decisions – both historical and recent – relating to intra-group financial transactions. The series analyses how courts apply the arm’s-length principle in practice and considers the implications of these court decisions for the transfer pricing of intercompany financial arrangements today.
This article focuses on one of the central issues in intra-group financing: the determination of arm’s-length interest rates. Two notable cases – the Norwegian ExxonMobil decision and the French Willink SAS decision – illustrate how courts approach this question and how their reasoning broadly aligns with the principles now articulated in Chapter X of the OECD Transfer Pricing Guidelines for Multinational Enterprises and Tax Administrations.
Chapter X emphasises that intra-group financial transactions must first be accurately delineated before any pricing analysis can be undertaken. An arm’s-length interest rate cannot be justified solely because it falls within a benchmarking range or mirrors another intra-group arrangement. Rather, it must reflect:
The borrower’s creditworthiness and financial capacity;
The purpose and terms of the financing;
Special contractual features such as subordination or convertibility;
The realistically available options of both borrower and lender; and
The prevailing market conditions at the time of the transaction.
Courts and tax authorities therefore assess whether the economic reality and the contractual terms align, and whether the selected comparables demonstrate a sufficient degree of comparability to provide a reliable arm’s-length benchmark. Ultimately, a defensible interest rate must be grounded in a coherent economic rationale that explains how independent parties would evaluate and price the transaction, rather than relying solely on mechanical models.
The ExxonMobil case
The Norwegian ExxonMobil case concerned a back‑to‑back financing structure. In April 2009, Exxon Overseas Corporation Inc. granted ExxonMobil Production Norway Inc. (EPNI) a NOK 20 billion loan facility maturing in March 2019. The loan carried an interest rate of three‑month NIBOR (Norwegian Interbank Offered Rate) plus 30 basis points and included a margin step‑up clause triggered by a significant deterioration in EPNI’s creditworthiness. Later that same year, rather than repaying the loan following the generation of surplus liquidity from asset disposals, EPNI extended a NOK 20 billion loan on substantially identical terms to another group entity, ExxonMobil Delaware Holdings Inc.
While the Norwegian tax authorities did not challenge the inbound financing arrangement, they considered the 30-basis point margin on the outbound loan to be too low for a long-term borrower with an AA+ equivalent credit profile as of November 2009.
In doing so, the court rejected the taxpayer’s reliance on a limited set of third‑party loans with similarly low margins, finding that there was insufficient evidence demonstrating comparability in terms of risk profile and surrounding circumstances. The court insisted that each intra-group loan must be evaluated and priced independently, as though it had been concluded between unrelated parties, and anchored its arm’s-length assessment in broader market evidence. Importantly, the fact that the arrangement formed part of a back‑to‑back structure, together with the inclusion of a step‑up clause, was not regarded as sufficient to establish that the pricing satisfied the arm’s-length principle.
Although rendered prior to the introduction of Chapter X, the judgment reflects many of its core principles: each intra-group financing transaction must be assessed on its own merits, and the pricing analysis must be grounded in observable market evidence rather than internal symmetry or purely mechanical benchmarking approaches. One aspect that Chapter X addresses more explicitly – but which the court did not explore in depth – is whether EPNI performed functions comparable to those of a financing entity and possessed the financial capacity to assume and manage the risks associated with the outbound loan.
The Willink SAS case
The Willink SAS case concerned intra-group convertible bond financing. In that case, the French tax authorities considered the interest rate applied to be excessive and challenged the methodology used by the taxpayer to support it. Willink SAS had relied on a synthetic credit rating generated through Moody’s RiskCalc, together with external refinancing transactions and bond market comparables, while also considering specific features of the instrument, including its maturity, subordinated nature, and conversion rights.
The French tax authorities criticised the use of synthetic credit ratings on the basis that they were inherently approximate. Both the Administrative Court and the Administrative Court of Appeal endorsed this critique.
The Conseil d’État (the French Supreme Administrative Court) overturned these decisions and ruled in favour of the taxpayer. Adopting a pragmatic approach, the court recognised that financial markets rarely provide perfectly identical comparables and that the arm’s-length principle does not require exact equivalence. It accepted that synthetic credit rating tools can legitimately support the determination of an arm’s-length interest rate, provided that they are applied consistently, based on reliable data, and supplemented by a qualitative assessment of the borrower’s risk profile and the specific characteristics of the financial instrument.
Implications of the rulings
Taken together, the ExxonMobil and Willink SAS decisions underscore that the determination of an arm’s-length interest rate ultimately depends on the credibility of the underlying creditworthiness analysis, the accurate delineation of the transaction, and the existence of a coherent economic rationale, rather than on formalistic structures or purely mechanical methodologies.
