A. On-Site Inspection Powers and the Approach of the Turkish Competition Board
Article 15 of Law No. 4054 on the Protection of Competition (“Law No. 4054”) authorizes experts of the Turkish Competition Authority (“Authority”) to conduct inspections at undertakings and associations of undertakings where necessary to perform their duties under the Law. Accordingly, experts may examine and copy the books, documents, and electronic records of undertakings during on-site inspections. However, this power is not unlimited.
The administrative authority must exercise its statutory powers strictly within the “subject matter and purpose” defined by the allegations and suspicions that justify the inspection. The Turkish Competition Board’s (“Board”) case-law clearly states that this power must be linked to the subject of the investigation[1].
While the Board enjoys broad discretion in technical assessments, case-law emphasizes that the principle of proportionality is the key for reviewing the legality of administrative acts[2]. This approach is critical in determining the legal nature of on-site inspections. An inspection is a limited power serving to clarify a specific allegation of infringement. If digital data collection extends to large datasets unrelated to the investigation, it raises concerns at the “necessity” and “proportionality” stages of the proportionality test.
In the Board’s practice, the scope of on-site inspection powers has expanded over time. In several decisions, the Board has treated the review of email correspondence and internal digital archives as standard practice. Where data is collected and sifted on-site, a copy of the documents obtained is left with the undertaking. If privileged documents are involved (e.g., attorney-client communications), objections are raised at that moment, and documents identified as privileged are excluded from the records through minutes prepared on-site[3].
Where on-site review is not feasible, the data may be copied and brought to the Authority’s premises for examination and sifting. In such cases, it is crucial to determine whether and how undertakings can assert privilege and at what stage this right may be exercised[4].
In fact, when data is copied and transferred to the Authority’s premises, issues may arise regarding the handling of undertakings’ rights-based objections and the safeguarding of their privilege claims. Indeed, “digital evidence collection processes involve large volumes of data, which may include privileged information and documents”[5].
The European Commission (“Commission”), recognizes data collection powers as valid only if they remain limited to the subject matter and purpose, respect the right of defense, and comply with the principle of proportionality[6].
In Türkiye, under the Authority’s traditional on-site inspection practice, the sifting process is conducted within the undertaking. Certain evidence identified through this process are transferred to the Authority’s premises via CD or external storage devices for further review. Copies of the collected documents are also left with the undertaking, as recorded in the minutes and delivered to authorized representatives. Accordingly, any claims or objections regarding privilege are handled simultaneously.
In its investigation decision dated 01.10.2018 and numbered 18-36/583-284, the Authority addressed allegations that digital evidence collection violated privilege rights. Referring to Article 15 of Law No. 4054, the Authority confirmed its power to collect digital evidence and stated that, during on-site inspections, it assigns a “hash value” to the collected data stored on CDs. A sealed copy of the CD is left with the undertaking. On this basis, the Authority concluded that copying data in digital form does not constitute an unlawful act[7].
B. Digital Data Imaging and the Principle of Proportionality
Section A of this article explains the Board’s on-site inspection powers and its approach to the imaging of digital data. In this context, we may refer to the Turkish Constitutional Court’s recent landmark decision addressing claims that the Board’s inspection powers are unconstitutional and infringe fundamental rights and freedoms.
In its decision dated 06.11.2025 (file no. 2023/174, decision no. 2025/224) the Constitutional Court focused its review on the phrase “where deemed necessary” in Article 15 of Law No. 4054. In doing so, the Court struck a balance between normative flexibility and constitutional foreseeability, recognizing that, particularly in economic regulation, the legislature may employ a degree of abstraction in technical areas. Rather than adopting a rigid and restrictive normative model, the Court preferred a framework that can be concretized through interpretation, in light of the dynamic nature of competition law. The Court’s assessment placed particular emphasis on the need for speed and effectiveness in on-site inspections.
The Court implicitly acknowledged that anti-competitive practices are often carried out covertly and that evidence can be swiftly destroyed; requiring prior judicial authorization could therefore render competition enforcement ineffective. The decision illustrates that the Court prioritizes the protection of the economic order when defining the constitutional limits of administrative powers.
Against this background, one of the most controversial practices in digital inspections is system imaging. The full duplication of a hard drive or server inevitably results in the Authority obtaining large volumes of data unrelated to the investigation. This makes the application of the constitutional principle of proportionality essential.
The proportionality analysis requires a three-step assessment:
- Is digital imaging suitable for the purposes of the investigation?
- Is it necessary to obtain digital data in this manner?
- Is there a reasonable balance between the collection of digital data and the alleged infringement under investigation?
If a targeted review limited to specific folders, date ranges or employee accounts is feasible, imaging the entire system may fail to satisfy the necessity requirement.
European Union practice provides useful guidance. While the Court of Justice of the European Union (“CJEU”) recognizes the European Commission’s broad investigative powers in competition cases, it consistently holds that such powers must be linked to a “specific and concrete suspicion of infringement”[8]. The Commission’s inspection powers are subject to judicial review and must be interpreted narrowly in light of fundamental rights. The CJEU has emphasized that the scope of an inspection decision must be clear and precise, and that undertakings must know the nature of the suspected infringement in order to exercise their rights of defense. It has also acknowledged that these powers cannot be exercised arbitrarily and constitute an interference with fundamental rights. This case-law demonstrates that far-reaching tools such as digital imaging must operate within defined limits[9].
In the Turkish legal system, and in line with the Commission’s case-law, Article 15 of Law No. 4054 was amended on 16.06.2020 to clarify the methods for examining digital data. Subsequently, the Board issued the Guidelines on the Examination of Digital Data in On-Site Inspections dated 08.10.2020 (decision no. 20-45/617) (“Digital Inspection Guidelines”). The Guidelines state that data copied during on-site inspections will benefit from privilege protections where applicable. However, they do not set out procedural details on when and how privilege claims must be raised.
C. Keyword Searches and the Relevance Problem
Keyword-based filtering forms the technical backbone of digital inspections. However, a keyword match does not necessarily indicate evidence linked to an infringement. In EU practice, the “relevance review” process during inspections is subject to specific procedural safeguards. In Deutsche Bahn v Commission[10], the General Court emphasized that the Commission must exercise its inspection powers within the limits of the suspected infringement and held that collecting evidence on matters not covered by the inspection decision may be unlawful.
A similar debate exists in Türkiye. In several decisions of the Board, digital correspondence obtained during inspections has served as key evidence. However, the link between such correspondence and the scope of the investigation is not always clear. Therefore, the method for defining keyword sets and the transparency of the filtering process are critical to the effective exercise of the right of defense.
Technically, keyword searches function as a filtering mechanism that isolates potentially relevant documents within large datasets. In practice, however, this method acts as an invisible threshold that determines the scope of the evidence. The choice of keywords, language variations, date ranges and user accounts effectively defines the body of evidence in the investigation.
Accordingly, defining the keyword set is not merely a technical choice but an act with legal consequences. If the keyword set is too broad, large volumes of unrelated data may fall within the scope of the review; if it is too narrow, potentially relevant data may be overlooked. The process of selecting keywords should therefore be seen as a technical domain where the “necessity” and “proportionality” elements of the proportionality test are put into practice.
Another issue is the conflation of “matching” with “relevance.” Digital systems can identify all documents containing a given term, but not all such documents are related to the alleged infringement. In competition law, terms such as price, market, quota, discount, and allocation are commonly used in ordinary commercial contexts and may carry different meanings depending on the context.
For this reason, keyword matches alone cannot be treated as evidence of infringement; the content and context must be assessed separately. Otherwise, keyword searches risk becoming an “automated suspicion-generation mechanism.” It is therefore essential that the review process combine technical expertise with legal assessment to ensure the effective protection of the right of defense.
Transparency in keyword searches is a separate concern. If filtering criteria and search parameters are not clearly recorded in the inspection minutes, subsequent judicial review may be hindered. Recording which keywords were selected and on what basis provides legal certainty for the Authority and gives concrete effect to the undertaking’s right of defense. In EU practice, more detailed procedural rules governing filtering are seen as reducing the risk of arbitrariness in digital inspections. Developing similar procedural transparency in Türkiye would strengthen the legitimacy of the digital evidence regime.
Finally, keyword searches carry a risk of ex post expansion. If documents uncovered during the inspection give rise to new suspicions, it may be possible to broaden the search terms. However, any such expansion must remain within the scope of the original inspection decision.
Otherwise, an inspection initially authorized for a specific allegation may evolve into a general data search. For this reason, any expansion of the keyword set should be duly justified and recorded, as required by the principles of proportionality and legal certainty.
D. Attorney–Client Privilege (“Legal Privilege”)
Attorney-client privilege is a fundamental component of the right of defense in competition investigations. This principle is clearly recognized in EU case law. In AM & S Europe v Commission[11], the Commission accepted that correspondence between an independent lawyer and a client must be protected and treated this protection as an integral part of the right of defense.
In Akzo Nobel v Commission[12], however, the Commission held that communications with in-house counsel do not fall within the scope of legal privilege. This decision draws an important boundary for the protection of corporate communications.
In the Turkish legal system, these landmark Commission decisions are effectively reflected in the Board’s practice. Although Turkish law does not explicitly regulate legal privilege, there is a clear need for similar protection based on the right of defense and the principle of the independence of the legal profession. In practice, the Board places particular emphasis on protecting correspondence with external counsel in line with international standards. However, the procedures and limits of this protection remain unclear. This creates a need for clearer rules on how documents containing legal advice should be filtered during digital inspections.
In AM & S Europe and Akzo Nobel, the Commission acknowledges that communications between a lawyer and a client cannot be disclosed or compelled to be disclosed in administrative or judicial proceedings. This principle constitutes a generally recognized form of protection under “attorney-client privilege”, acknowledged both internationally and in domestic legal systems. The Commission’s case-law places this principle within the scope of the right to a fair trial under Article 6 of the European Convention on Human Rights (“ECHR”), effectively recognizing it as a “first-generation right”.
The European Court of Human Rights (“ECtHR”) has also consistently held that lawyer-client communications are privileged[13].
In Erdem v Germany[14], the Court ruled that correspondence between a lawyer and a client is a fundamental right directly linked to the right of defense and may be restricted only in exceptional circumstances, subject to safeguards aimed at preventing abuse.
In light of this fundamental protection, competition law calls for a careful balance of interests, as effective enforcement depends on thorough evidence review and the complete collection of evidence. The Authority experts have broad powers to collect evidence, and the Constitutional Court has recently rejected claims that these powers violate constitutional rights. However, these powers are not unlimited. Attorney-client privilege is one of the key constraints. Any arbitrary restriction of the right of defense by an administrative authority would be incompatible with the rule of law and is not an outcome the Authority itself endorses. Moreover, Article 36 of Attorneyship Law No. 1136 expressly recognizes the confidentiality of the lawyer–client relationship.
The principle of freedom of evidence is fundamental in competition law. However, evidence must be obtained lawfully. Article 38 of the 1982 Constitution explicitly provides that unlawfully obtained evidence cannot be used. Accordingly, attorney-client privilege operates as a safeguard in on-site inspections and forms part of the protection of the right of defense. That said, not all communications between a lawyer and a client fall within the scope of this privilege.
During on-site inspections, the Authority first examines whether the lawyer is independent or acts as in-house counsel within the undertaking. For competition law purposes, privilege applies only to communications between an “independent lawyer” and the undertaking (client). Case-law emphasizes that in-house lawyers do not enjoy the same level of professional independence as external counsel, as they are bound by an employment relationship and its inherent obligations[15].
It is also essential that the communication in question relates to the client’s “right of defense”.
In its CNR decision[16], the Board underlined that attorney-client privilege serves as a guarantee of the right of defense, referring to the lawyer’s duty of confidentiality. In the same decision, with reference to Article 130 of Criminal Procedure Code No. 5271, the Board confirmed that communications between a lawyer and a client made in the context of the right of defense are privileged[17].
The Board has expressed its position clearly, in line with EU practice and international conventions: correspondence between an “independent lawyer” and the client undertaking concerning the right of defense falls within the scope of legal privilege and cannot be seized by the Board.
E. Opinion and Conclusion
Digitalization in competition law is an irreversible reality. However, advances in technical capacity should not blur legal boundaries. Both the practice of the Board and the case-law of the European Commission demonstrate that inspection powers, while broad, are not unlimited.
On-site inspections are tools to clarify suspected infringements; they are not general or indefinite digital data collection mechanisms. Accordingly, transparency in the selection of keyword sets, clear filtering mechanisms for legal privilege, and procedures to segregate data outside the scope of the investigation should be established. This approach allows a more balanced alignment between effective enforcement and the right of defense.
The legitimacy of competition law in the digital era depends not only on detecting infringements but also on the methods used and the constitutional safeguards applied. Given recent developments and the Board’s proactive approach, the ongoing adaptation of inspection processes to the digital context remains a central focus for effective oversight.
Gülşah Güven, LL.M., Partner
[1]https://www.rekabet.gov.tr/Karar?kararId=a11d6b34-767e-4055-9fc3-78bf84a2a437; https://www.rekabet.gov.tr/Karar?kararId=a88ca725-78b0-4565-81be-76389df52b64
[2] COUNCIL OF STATE, 13TH CHAMBER, FILE NO. 2022/1993, DECISION NO. 2022/2819, 22.06.202; COUNCIL OF STATE, ADMINISTRATIVE LITIGATION CHAMBERS BOARD, FILE NO. 2008/1410, DECISION NO. 2013/279, 31.01.2013
[3] https://one.oecd.org/document/DAF/COMP/GF(2018)7/en/pdf
[4] MICHALEK, M. (2015), Right to Defence in EU Competition Law: The Case of Inspections, University of Warsaw Faculty of Management Press, Warsaw
[5] https://www.rekabet.gov.tr/Dosya/oyku-sariaslan-20220915164117464.pdf
[6] European Commission Regulation 1/2003, Article 20(b)(c).
[7] https://www.rekabet.gov.tr/Karar?kararId=7276e920-23a5-4d66-9b0f-c5d9381d7c88
[8] https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:62005TJ0161
[9] https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:62018CJ0606_RES
[10] https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:62013CA0583
[11] https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex:61979CJ0155
[12] https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex:62007CJ0550
[13] Application no: 332/74 Foxley v United Kingdom, para.43; Campell v. United Kingdom 13590/88, para. 46; Application no: A220, S. v. Switzerland 28.11.1991
[14] Application no: 38321/97Erdem v. Germany
[15] AKZO: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex:62007CJ0550
[16] https://www.rekabet.gov.tr/Karar?kararId=bccc0964-45b9-4c34-b89b-0e7494e3f165
[17] https://www.rekabet.gov.tr/Karar?kararId=077e8e69-af12-4993-9b19-f6d646c9b43c
