UK Subsidy Control: Economic reasoning comes to the fore

In summary

• The UK subsidy control regime is placing increasing emphasis on clear, robust and economically coherent reasoning rather than purely procedural compliance 
• The commercial market operator test and principles assessment require well-evidenced narratives, credible counterfactuals and explicit links between policy objectives and intervention design 
• Economic analysis is also increasingly embedded early in decision making, shaping how subsidies are structured, justified and documented rather than reserved for disputes 
• As a result, economic analysis is becoming a core component of how subsidy decisions are designed, justified and defended 

The UK’s subsidy control regime was set out in the Subsidy Control Act 2022 (the Act), but is now evolvinbeing provided by the CMA’s Subsidy Advice Unit (SAU) and recent appeals at the Competition Appeal Tribunal (CAT), including Mr Weis v Greater Manchester Combined Authority, Bristol Airport  Ltd v Welsh Government and The New Lottery Company and others v The Gambling Commission.  

Togther, these developments suggest a growing practical emphasis on the quality, structure and evidential robustness of economic reasoning used to support subsidy decisions. For public authorities and delivery bodies, the emphasis is increasingly shifting from simply formal compliance with statutory tests towards ensuring that decisions can be clearly evidenced, and are economically coherent and defensible under any subsequent scrutiny.  

The change requires that economic analysis is considered from the outset and embedded within the investment rationale and structure. Such an approach aims to ensure that the investment can be robustly defended with an appropriate paper trail in the case of a challenge at the CAT, rather than relying on ex-post analysis or independent experts to defend decisions. 

The statutory framework consists of two parts:  

The first step is to determine whether a measure constitutes a subsidy under section 2 of the Act, based on four cumulative conditions: 

• Financial assistance provided by a public authority  
• Conferral of an economic advantage  
• Specificity  
• The effect on competition or investment  

The most economically significant element is the economic advantage test. In practice, this is assessed under the commercial market operator (CMO) principle: whether a rational private-sector operator, acting in comparable circumstances and with available information, would have made a similar decision on broadly comparable terms. 

This is an inherently counterfactual assessment of commercial rationality, and its robustness depends heavily on: 

• The availability of credible market benchmarks  
• The comparability of transactions or instruments  
• The assumptions used around pricing, risk and return  
• The extent to which the decision-making process is documented  

Recent CAT decisions, including Weis v GMCA, indicate that the focus is on whether the decision can be rationally reconstructed as commercially defensible (consistent with a judicial review standard rather than a full merits-based reassessment). 

For public authorities looking to make investments that are not deemed to be subsidies (eg on commercial terms), the practical implication is that CMO assessments are increasingly expected to be evidenced narratives of commercial logic, including a specific CMO assessment, not just procedural records. 

Where a measure is identified as a subsidy, it must then be assessed against the Schedule 1 principles, including: 

• Identification of a specific policy objective (often linked to market failure or equity considerations)  
• Assessment of incentive effects  
• Evaluation of impacts on competition and investment  
• An overall balancing exercise  

The CMA SAU’s updated guidance (August 2025) also reinforces the increased emphasis on analytical clarity, requiring clearer articulation of market failure and rationale for intervention , a more explicit link between the policy objective and economic mechanism, and a more structured assessment of distortive effects. 

In practice, this is leading to more disciplined economic articulation of policy intent and expected effects, particularly where schemes are complex or involve material market impacts. 

For authorities, this increasingly means that policy justification and economic reasoning need to be developed in parallel rather than sequentially, particularly at the design stage. 

Strikingly, in practice, economic analysis is not simply growing increasingly important for subsidy control; the way it is being used is also changing. 

In traditional competition litigation (for example, competition damages cases), economic experts are typically presented as independent witnesses. Competing models are tested through cross-examination before the CAT, with the tribunal acting as an arbiter between rival expert evidence. 

In subsidy control matters, by contrast, there is an increasing trend towards embedding economic analysis within the decision-making and submission process itself. 

Economic input is increasingly: 

• Used early in transaction structuring and option appraisal  
• Incorporated into internal decision papers and business cases  
• Reflected directly in submissions to the CMA SAU or evidential records for CAT review  
• This results in a less adversarial model of economic input. Rather than being primarily deployed at the dispute stage, economic analysis is part of the front-end justification of the decision. 

For public authorities, this has a practical implication: The strength of the subsidy decision is increasingly determined not when it is challenged, but by the clarity and coherence of the economic reasoning at the point the decision is made. 

The CMA SAU has now reviewed over 100 subsidies and schemes. Across its opinions, several consistent themes have emerged.

The articulation of market failure is improving, but the SAU continues to emphasise the need for: 

• A clearer definition of the underlying market failure  
• A more explicit link between that failure and the intervention design 

There is an increasing focus on ensuring that assessments of competition and investment effects consider: 

• Indirect impacts  
• Dynamic responses (entry, exit and investment displacement)  
• Broader market structure implications  

The balancing exercise remains an area of ongoing development. In practice, there is an increasing expectation that benefits and distortions are set out in a structured and evidenced manner, rather than being described narratively. 

Recent CAT cases, meanwhile, including Cardiff Airport and Allwyn, highlight the importance of how counterfactual scenarios are constructed and evidenced. 

Particular attention is being paid to the credibility of the “but for” world, the robustness of comparator selection, and the treatment of uncertainty within analysis.  

For public authorities looking to make investments or award subsidies, this reinforces the importance of ensuring that counterfactual reasoning is explicit, transparent and capable of being reconstructed from the decision record.

Across these developments, practical implications are emerging for public authorities and advisors: 

• CMO assessments are increasingly expected to be structured and evidenced economic narratives of commercial rationality  
• Principles assessments are becoming more explicit in their economic framing and internal logic  
• Both are increasingly reliant on the clarity of underlying analytical reasoning rather than post hoc justification  

Economic analysis is not only increasingly integrated into subsidy control decision-making, but is integrated in a way that is supportive of defensible decision design rather than adversarial dispute resolution. 

For public bodies, the key shift is practical rather than legal: They must ensure that subsidy decisions are supported by clear counterfactual thinking, well-evidenced CMO assessments and structured, principles-based analysis that can withstand scrutiny. 

In this context, economic analysis is becoming less a specialist add-on at the dispute stage and more a core component of how subsidy decisions are designed, justified and, ultimately, defended.