INTRODUCTION
To establish a competition law infringement, competition authorities must examine the legal nature of the conduct and support their findings with sufficient evidence. This process can be more complex in cases involving cartels, concerted practices and indirect exchanges of information between competitors. In such cases, competition authorities assess written messages, meeting records, price changes and economic data together.
This raises an important question: Is it enough to show that a competition law infringement was very likely to have occurred before imposing an administrative fine on an undertaking?
The answer is closely related to the standard of proof. The standard of proof refers to the level of certainty needed to accept a fact as proven. The burden of proof determines which party must prove that fact.
There are three main standards of proof in comparative law.
Balance of probabilities / Preponderance of the evidence: Under this standard, a fact is accepted as proven when it is more likely to have happened than not. This standard is commonly used in civil cases, especially in common law systems.
Clear and convincing evidence: This standard requires a higher level of certainty than the balance of probabilities. The available evidence must be strong, clear and reliable enough to show that the fact is highly likely to have occurred.
Beyond a reasonable doubt: This is a high standard of proof, mainly used in criminal proceedings. It requires the evidence to remove reasonable doubts about whether the alleged act took place.
The main difference between these standards is the level of certainty required. Their use in competition law depends on the legal system, the type of sanction and the approach of the courts.
I. DOES THE SERIOUSNESS OF AN ADMINISTRATIVE SANCTION CHANGE THE STANDARD OF PROOF?
Administrative fines for competition law infringements may have serious financial and commercial effects on undertakings. As these sanctions also have punitive and deterrent purposes, the appropriate standard of proof is an important legal issue.
Do serious administrative fines require competition law infringements to be proven to a level of certainty close to that required in criminal proceedings?
Different approaches to this question can be seen in the United Kingdom, the European Union and the United States.
United Kingdom: The JJB Sports Decision
The decision of the UK Competition Appeal Tribunal (CAT) in JJB Sports plc and Allsports Limited v Office of Fair Trading [2004] CAT 17 is an important example of the standard of proof in competition law.
The case concerned resale price fixing for football shirts. The CAT applied the balance of probabilities standard when assessing the competition law infringement. However, it also stated that the seriousness of the allegation and the possible penalties should be considered when assessing the strength of the evidence.
Paragraph 196 of the decision explains the balance of probabilities standard. Paragraph 206 states that, depending on the facts of the case, a single piece of evidence or even entirely indirect evidence may be enough to meet the required standard.
This approach shows the difference between the standard of proof and the strength of evidence. Even under the balance of probabilities standard, the reliability of the evidence and the way different findings support each other are important.
The JJB Sports decision therefore shows an approach in which the seriousness of the sanction is taken into account when assessing evidence, while the balance of probabilities remains the applicable standard.
European Union: Presumption of Innocence and Sufficiency of Evidence
In EU competition law, the burden of proof is regulated under Article 2 of Council Regulation No. 1/2003. Under this provision, the party or authority claiming an infringement of Article 101 or 102 TFEU must prove the infringement.
The rules on the sufficiency of evidence have mainly developed through the case law of the EU courts. These decisions give importance to reliable and consistent evidence, a sufficient level of certainty and the protection of the presumption of innocence.
The judgments of the Court of Justice of the European Union in Hüls v Commission (C-199/92 P) and Montecatini v Commission (C-235/92 P) are important examples of the application of the presumption of innocence in competition law cases.
Under this approach, competition infringements must be supported by sufficient evidence, and unresolved doubts must be considered in favour of the undertaking.
In investigations involving economic analysis, the reliability of the data, the accuracy of the methods used and the strength of the economic findings are also important.
Therefore, in EU competition law, the sufficiency of evidence is assessed together with fundamental legal rights and the economic conditions of each case.
United States: Different Standards for Different Legal Proceedings
In the United States, the standard of proof in competition law depends on the type of legal proceedings.
The beyond a reasonable doubt standard applies in criminal cases under the Sherman Act, including cases involving price fixing, market allocation and bid rigging.
In private civil antitrust cases, the general standard is preponderance of the evidence.
The US approach shows that similar anti-competitive conduct may be examined under different standards of proof, depending on the legal proceedings. It also shows the connection between the type of sanction and the required standard of proof.
The OECD Report of 2024
In 2024, the Organisation for Economic Co-operation and Development (OECD) published The Standard and Burden of Proof in Competition Law Cases. The report examines different approaches to proof in competition law and the role of economic analysis.
Published as No. 318 in the OECD Roundtables on Competition Policy Papers series, the report discusses the relationship between the standard of proof, the type of sanction, the nature of evidence and judicial review.
In investigations that require an assessment of economic effects, competition authorities need to compare different economic explanations and support their findings with reliable analysis.
This raises another question: Could a higher standard of proof provide stronger legal protection for undertakings while also making it harder to punish real competition law infringements?
There are two main risks. The first is a false positive, where an undertaking is wrongly found to have infringed competition law. The second is a false negative, where a real infringement cannot be proven and therefore remains without a sanction.
A higher standard of proof provides stronger protection against incorrect findings, but it can make secret cartels harder to detect and prove. A lower standard may make enforcement easier, but it can increase the risk of incorrect decisions.
The OECD report shows the importance of considering the reliability of economic analysis, the nature of evidence and effective judicial review when discussing standards of proof.
For this reason, competition law must find a balance between the legal rights of undertakings and the effective enforcement of competition rules.
II. SUFFICIENCY OF INDIRECT EVIDENCE IN PROVING COMPETITION LAW INFRINGEMENTS
Competition law infringements, especially cartels and concerted practices, often take place in secret. Competition authorities therefore use indirect evidence, such as price changes, market conduct, communication records and economic data, alongside direct evidence.
However, can different pieces of indirect evidence, which support each other, be sufficient to prove an infringement when direct evidence is not available?
The answer is closely related to the joint assessment of evidence and the examination of alternative economic explanations.
The judgment of the Court of Justice of the European Union in A. Ahlström Osakeyhtiö and Others v Commission (Wood Pulp) is important in assessing parallel market conduct.
The Court stated that, where a concerted practice is inferred from parallel conduct alone, it is necessary to examine whether there is another reasonable economic explanation for that conduct.
For example, when undertakings in the same market increase their prices at similar times, this may suggest coordination. However, common cost increases, exchange rate changes or market demand may also explain similar price movements.
The US Supreme Court's decision in Matsushita Electric Industrial Co. v Zenith Radio Corp., 475 U.S. 574 (1986), also highlights the importance of considering whether undertakings may have acted independently when assessing indirect evidence.
These decisions show that the strength of indirect evidence must be assessed in light of the economic and legal conditions of each case.
In addition to parallel prices, communication between undertakings, exchanges of future pricing information and later market conduct may be assessed together. The connection between these findings can provide stronger evidence of anti-competitive coordination.
There is an important difference between the standard of proof and the method used to assess evidence. The standard of proof determines the required level of certainty. The joint assessment of evidence helps determine whether the available evidence reaches that level.
Therefore, a single piece of evidence may have limited value on its own but may become more important when assessed with other findings. The key point is whether the evidence is consistent and reliably supports the infringement claim.
III. THE STANDARD OF PROOF IN TURKISH COMPETITION LAW: DO THE TURKISH COMPETITION BOARD AND THE COUNCIL OF STATE FOLLOW THE SAME APPROACH?
In Turkish competition law, discussions on the standard of proof focus on the approach of the Turkish Competition Board and the judicial review of its decisions by administrative courts.
Article 4 of Law No. 4054 on the Protection of Competition includes a presumption concerning concerted practices. Under this provision, certain market conditions may create a presumption that undertakings have engaged in a concerted practice. Undertakings may challenge this presumption by providing economic and reasonable explanations for their conduct.
A legal presumption allows a conclusion to be drawn from certain facts, while the standard of proof determines the level of certainty required to establish an infringement.
The Turkish Competition Board's Approach to the Standard of Proof in the MediaMarkt Decision
The Turkish Competition Board's MediaMarkt decision, dated 2 April 2026 and numbered 26-11/343-130, includes important assessments of the standard of proof in Turkish competition law.
The decision is particularly important because the Board examined both the sufficiency of the evidence and the standard of proof required in competition law, with reference to comparative law.
The investigation concerned allegations of indirect information exchange and coordination of retail prices between MediaMarkt, Teknosa and Vatan through Fakir.
In its defence, MediaMarkt argued that the Board should apply the beyond a reasonable doubt standard to establish a hub-and-spoke cartel infringement.
The Board first explained its approach to the assessment of evidence. In paragraph 160, referring to its earlier decision dated 15 December 2022 and numbered 22-55/863-357, the Board stated that cartel evidence should be "clear, convincing and consistent" when assessed as a whole.
This approach focuses on how different pieces of evidence support each other in proving an infringement.
The Board then explained three main standards of proof in comparative law.
Under the balance of probabilities standard, it is enough to show that a fact is more likely to have occurred than not.
The clear and convincing evidence standard requires strong and specific evidence showing that a fact is highly likely to have occurred.
The beyond a reasonable doubt standard is mainly used in criminal proceedings and requires a very high level of certainty.
After these explanations, the Board focused on the legal nature of the sanction and the legal interests protected by the relevant rules.
In paragraph 163, the Board stated that legal systems dealing with competition infringements through administrative proceedings generally apply the balance of probabilities or clear and convincing evidence standards. In criminal competition law cases, the beyond a reasonable doubt standard applies.
The Board supported its assessment with the decisions of the UK Competition Appeal Tribunal in JJB Sports plc and Allsports Limited v Office of Fair Trading [2004] CAT 17 and Claymore Dairies v OFT [2003], as well as the OECD's 2024 report, The Standard and Burden of Proof in Competition Law Cases.
The most important part of the MediaMarkt decision is the Board's clear explanation of its own approach after this comparison.
The Board considered that the balance of probabilities or clear and convincing evidence standards may be used to establish competition infringements subject to administrative sanctions. Under this approach, it is sufficient to show, through clear, consistent and specific evidence, that an infringement is more likely to have occurred than not.
Does this assessment indicate a change in the Turkish Competition Board's approach to the standard of proof?
In earlier Turkish competition law decisions, the Board sometimes placed emphasis on proving infringements beyond all reasonable doubt. In the MediaMarkt decision, however, the Board expressly discussed the balance of probabilities and clear and convincing evidence standards based on the administrative nature of competition law sanctions.
In this respect, the decision may indicate a move towards an approach that requires a different level of certainty from the high standard mentioned in some earlier decisions.
The Board also explained its approach to the freedom of evidence. In paragraph 164, it stated that written messages, meeting notes, emails and instant messages may be used to prove an infringement. The content of the evidence and its ability to establish the facts are more important than the undertaking from which it was obtained.
In the case, the Board assessed WhatsApp messages between Fakir employees, Instagram messages between MediaMarkt and Fakir, and the price movements of electronics retailers together.
Based on the connection between these findings, the Board identified price coordination through the supplier and examined the retailers' expectations about their competitors' future price changes.
Overall, the MediaMarkt decision is important because it provides a clearer explanation of the Turkish Competition Board's approach to the standard of proof.
The Standard of Proof in Judicial Review by the Council of State
In its competition law judgments, the Turkish Council of State (Danıştay) gives importance to specific evidence, the connection between an undertaking and the alleged infringement, and the sufficiency of the evidence.
In some judgments concerning the 12 Banks case, the expression beyond a reasonable doubt was used. This raises an important legal question when compared with the approach of the Turkish Competition Board.
Does the Council of State's requirement for strong and clear evidence mean that it applies a different standard of proof from the Turkish Competition Board?
Two points are important in answering this question. The first is whether a court adopts a particular standard of proof as a general legal rule. The second is whether the court finds the available evidence sufficient to establish an infringement in a specific case.
For example, one of the main issues in the 12 Banks case was whether the conduct of different undertakings could be linked to a common plan. The judicial assessment therefore also focused on proving each undertaking's connection to the alleged infringement.
The judgment of the 13th Chamber of the Turkish Council of State, dated 15 May 2024 (Case No. 2024/846, Decision No. 2024/2183), also provides an important perspective on the level of suspicion required to initiate a full investigation. Although the majority upheld the dismissal of the action challenging the Board's decision not to open an investigation, the dissenting opinions emphasised the need to initiate an investigation where the allegations could not be sufficiently clarified during the preliminary investigation stage. This distinction highlights the difference between the level of suspicion required to open an investigation and the standard of proof necessary to establish an infringement in a final decision.
At the preliminary stage, evidence showing that a suspected infringement requires further examination may be sufficient. At the final stage, the undertaking's responsibility for the infringement must be supported by specific evidence.
When the MediaMarkt decision and the Council of State's approach are considered together, the reliability and sufficiency of evidence are important in both processes.
However, the legal terms used and the way these standards are applied may lead to different assessments.
For this reason, Turkish competition law needs a clear understanding of both the applicable standard of proof and its practical use when assessing evidence and reviewing administrative decisions.
CONCLUSION
The standard of proof is an important part of the balance between effective competition law enforcement and the protection of undertakings' legal rights.
Comparative law shows that the applicable standard depends on the legal system, the type of sanction and the relevant procedural rules. The balance of probabilities is important in the United Kingdom, while EU case law focuses on the sufficiency of evidence and the presumption of innocence. In the United States, different standards apply to criminal and civil proceedings.
The OECD's 2024 report also highlights the importance of economic analysis, the nature of evidence and judicial review.
In Turkish competition law, the MediaMarkt decision is important because it clearly discusses the applicable standards of proof and explains how evidence should be assessed together. In judicial review, the Council of State focuses on specific evidence and the responsibility of each undertaking.
The main question in competition law is therefore both which standard of proof applies and how the available evidence meets that standard.
Assessing evidence as a whole, considering alternative economic explanations and protecting the rights of defence are essential for reliable infringement findings. This approach can support a fair and predictable balance between effective competition law enforcement and the legal protection of undertakings facing serious administrative sanctions.
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