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Efser Zeynep Ergun

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How to File a Complaint with the Turkish Competition Authority (TCA): Step‑by‑step

By Global Law Experts

– posted 27 minutes ago

Updated August 6, 2026, reflects 2026 TCA enforcement trends.

Understanding how to file a complaint with the Turkish Competition Authority is essential for any business, trade association, or individual that suspects anti‑competitive conduct in or affecting the Turkish market. The Rekabet Kurumu (Competition Authority) accepts complaints concerning cartels, abuse of dominance, concerted practices, resale price maintenance, information‑exchange arrangements, and other exclusionary behaviour prohibited under Act No. 4054 on the Protection of Competition. With the TCA signalling a renewed enforcement push throughout 2026, including higher fines and more rigorous documentary screening, complainants who prepare thorough, well‑structured submissions stand a materially better chance of triggering a formal investigation.

This guide sets out the eligibility requirements, the complete TCA complaint process in numbered steps, every document you will need, realistic timelines, estimated costs, and the most common pitfalls practitioners encounter.

Overview of the process and who it applies to

Any natural person, undertaking, trade association, or public body may file a complaint with the Turkish Competition Authority. There is no requirement that the complainant be a direct competitor or customer of the alleged infringer; it is sufficient that the conduct complained of falls within the scope of Act No. 4054. Complaints may relate to agreements restricting competition (Article 4), abuse of a dominant position (Article 6), or mergers and acquisitions that were not properly notified (Article 7).

Complaints are directed to the Rekabet Kurumu, which houses both the professional staff (the Presidency and case‑handling departments) and the Competition Board, the decision‑making body that ultimately determines whether to open a preliminary inquiry or a full investigation. Submissions can be made through the TCA’s online complaint notice system or by post to the Authority’s Ankara headquarters. The TCA does not prescribe a mandatory complaint form; a well‑structured written submission accompanied by supporting evidence is accepted.

Early indications suggest that the 2026 enforcement environment favours complainants who submit complete, evidence‑rich dossiers. The sections below explain exactly what “complete” means in practice and walk through each stage of the procedure from evidence gathering to Board decision.

Eligibility and requirements for filing a TCA complaint

Before preparing your submission, confirm that you meet the eligibility criteria and understand the jurisdictional reach of the Authority.

Who may complain

There is no standing threshold. Competitors, suppliers, customers, consumer associations, employees (typically through counsel), trade bodies, and even individuals may submit a complaint. Foreign companies and foreign nationals are equally entitled to file, provided the alleged conduct has effects within Turkey. The TCA does not charge a filing fee of any kind.

Jurisdiction

The TCA has jurisdiction over anti‑competitive conduct that takes place in Turkey or that produces effects in the Turkish market, regardless of where the undertakings concerned are incorporated. This effects‑based approach means that a foreign company complaint is viable whenever the alleged cartel, abuse, or concerted practice distorts competition within Turkish territory. Foreign complainants should, however, be prepared to address the jurisdictional nexus explicitly in their submission.

Confidentiality and anonymity

Complainants may request that their identity and specific commercial information be treated as confidential. The TCA’s established practice is to assess confidentiality requests on a case‑by‑case basis: trade secrets, commercially sensitive pricing data, and customer lists are routinely protected. To invoke protection, attach a separate confidentiality cover sheet identifying each confidential document and providing a brief justification. Note that a fully anonymous complaint, one that does not disclose the complainant’s identity even to the TCA, is possible but may limit the Authority’s ability to follow up and request clarification.

When to involve counsel

Legal representation is not formally required, but experienced antitrust counsel should be engaged when: the matter involves complex economic evidence or market definition issues; the complainant is a foreign entity unfamiliar with Turkish procedural norms; the complaint may provoke retaliatory dawn raids against the complainant’s own operations; or the complainant intends to seek interim measures. Counsel also ensures that the submission meets the documentary and translation standards the TCA expects, reducing the risk of an administrative request for supplementary information that delays the process. For a list of qualified practitioners, consult the Global Law Experts lawyer directory.

How to file a complaint with the Turkish Competition Authority: step‑by‑step procedure

The TCA complaint process follows a broadly predictable sequence. Below are the six core steps a complainant must take, followed by the Authority’s own procedural stages.

Step 1. Prepare the factual statement and evidence index

Begin by assembling a detailed chronological statement of facts. This document should identify every party involved, describe the relevant product or service market, set out the specific anti‑competitive conduct alleged, and cross‑reference supporting exhibits. An evidence index, a numbered table linking each factual assertion to its corresponding document (contract, email, invoice, screenshot, pricing table), is critical. The TCA’s case teams use the evidence index to triage complaints quickly; a disorganised submission slows assessment and may result in a request for supplementary information.

Step 2. Draft the legal grounds under Act No. 4054

Identify the specific provisions of Act No. 4054 that the alleged conduct infringes. For cartel activity or concerted practices, cite Article 4. For abuse of dominance, predatory pricing, refusal to deal, tying, discriminatory terms, cite Article 6. Each legal ground should be supported by a concise argument paragraph explaining how the facts satisfy the statutory elements. While the TCA is not bound by the complainant’s legal characterisation, a clearly articulated legal basis demonstrates seriousness and helps the case team frame its initial assessment.

Step 3. Submit via the online portal or by post

The TCA accepts complaints through its online notice system (referenced on the Rekabet Kurumu website under the complaint submission guidance) or by physical delivery to the Authority’s Ankara headquarters. Online submissions should include uploaded PDF attachments of all supporting documents. Postal submissions must be signed by the complainant or an authorised legal representative and should include a USB drive or CD containing electronic copies of all exhibits. Whichever channel you choose, the date of filing is day zero for all subsequent procedural timelines.

Step 4. Request confidentiality for sensitive materials

If your submission contains trade secrets, commercially sensitive data, or information that could identify a whistleblower, prepare a confidentiality cover sheet. This document should list every exhibit for which protection is sought, the category of information (trade secret, personal data, pricing data), and a brief justification. Submit both a redacted version (for potential disclosure to the respondent during any investigation) and an unredacted version marked “Confidential, for TCA use only.” The TCA typically accepts well‑justified confidentiality requests, but over‑redaction, removing so much information that the case team cannot assess the complaint, is a common pitfall that should be avoided.

Step 5. Receive acknowledgement and case number

After submission, the TCA Secretariat conducts an administrative completeness check. Within approximately 1–14 days, the complainant should receive an acknowledgement confirming receipt and assigning a case reference number. If the submission is incomplete, for example, a missing power of attorney or unsigned cover letter, the Secretariat will issue a request for supplementary documents. Retain the case number for all future correspondence.

Step 6. TCA initial assessment and next steps

The Authority’s case team reviews the complaint to determine whether it falls within the TCA’s jurisdiction and whether the evidence presents a prima facie case of an infringement. This initial assessment typically takes 30–90 days, though more complex matters may require additional time. The possible outcomes at this stage are: (a) the complaint is dismissed for lack of jurisdiction or insufficient evidence; (b) the TCA requests further information from the complainant or third parties; (c) the Board opens a preliminary inquiry (ön araştırma); or (d) the Board launches a full investigation (soruşturma). If a preliminary inquiry is opened, it may itself lead to a full investigation or to closure.

Timeline summary table

Step	Who does it	Typical duration
1. Evidence gathering and complaint drafting	Complainant / counsel	1–4 weeks (complexity dependent)
2. Submission via Rekabet Kurumu online portal or by post	Complainant / counsel	Immediate, file date = day 0
3. Acknowledgement and administrative completeness check	TCA Secretariat	1–14 days
4. Initial assessment (jurisdiction and prima facie review)	TCA case team	30–90 days (typical practice range)
5. Decision to open preliminary inquiry or dismiss	Competition Board	1–4 months from receipt (varies)
6. Full investigation (if opened)	TCA investigation team	6–18 months (case dependent)
7. Board decision, sanctions, or commitments	Competition Board	Variable, follows investigation calendar
8. Judicial appeal (if Board decision is adverse)	Parties / administrative courts	60‑day appeal window

Documents needed for a TCA complaint

A complete submission package significantly increases the likelihood of a prompt initial assessment. The table below lists the documents the TCA expects or strongly recommends. All core documents should be in Turkish; where originals are in another language, certified Turkish translations should accompany them or the complainant should state that translations will be provided on request.

Document	Notes
Cover letter / complaint letter (signed)	One‑page summary identifying the complainant, the respondent(s), the market, and the relief sought. Signed by the legal representative or authorised officer. Include full contact details.
Detailed statement of facts (chronology)	Clear timeline of events: dates, parties, products/services, and alleged anti‑competitive acts. Cross‑reference paragraph numbers to supporting exhibits.
Evidence index (table of exhibits)	Numbered list linking each exhibit to the relevant factual assertion. Include document type, date, author, and a short description.
Documentary evidence	Contracts, invoices, emails, screenshots, price lists. Prefer PDF originals. Label each exhibit consistently with the evidence index.
Affidavits / witness statements	Signed statements from witnesses or former employees. If anonymity is needed, note this in the confidentiality cover sheet.
Market data (sales, volumes, prices)	Spreadsheets with source references and calculations. Provide ranges if exact figures are commercially sensitive; offer to supply originals under confidentiality.
Corporate documents	Trade registry extract or incorporation documents for the complainant (and, if available, the respondent). Foreign entities should provide notarised certificates with apostille.
Power of Attorney	Required if counsel files on behalf of the complainant. Must authorise counsel to file the complaint and receive TCA correspondence.
Confidentiality cover sheet and justification memo	Lists each confidential exhibit, the category of protected information, and a brief justification under TCA confidentiality criteria.
Certified translations	Certified Turkish translations of all key non‑Turkish documents. At minimum, state that translations will be provided upon TCA request.

Sample complaint wording

A TCA complaint letter typically opens with a formal heading identifying the Authority, the complainant, and the respondent(s), followed by a section headed “Subject” that summarises the infringement type (e.g., “Complaint regarding a concerted practice in violation of Article 4 of Act No. 4054”). The body should then proceed in numbered sections: (1) identity and standing of the complainant; (2) identity of the respondent(s); (3) relevant market; (4) statement of facts; (5) legal analysis; (6) evidence summary with exhibit references; (7) relief sought; and (8) confidentiality request (if applicable). The letter should close with a signature block, date, and a list of annexes. A downloadable sample complaint template and evidence index spreadsheet are available to complement this guide.

Timeline and key deadlines in the TCA complaint process

There is no single statutory clock that governs every stage of a TCA complaint. The table below consolidates the practical deadlines and typical durations that complainants should plan around. Exact timelines vary by case complexity, the volume of evidence, and the TCA’s current caseload.

Action	Statutory or practical deadline	Notes
Administrative acknowledgement	1–14 days (practical)	TCA Secretariat issues receipt and case reference number.
Initial assessment period	30–90 days (common practice range)	No fixed statutory day‑count; duration depends on complexity and information requests.
Board decision to open preliminary inquiry	Typically 1–4 months from receipt	The Board may also decide to open a full investigation directly.
Full investigation duration	6–18 months (case dependent)	Complex cartel investigations may take longer; the Board sets an internal calendar.
Interim measures (if requested)	Days to weeks (case dependent)	The TCA may impose interim measures where there is a risk of serious and irreparable harm to competition.
Appeal of Board decisions	60 days to administrative court	Standard administrative appeal window under Turkish administrative procedure.

Industry observers expect that the TCA’s 2026 enforcement posture may lead to faster initial assessments in priority sectors, particularly digital markets, pharmaceuticals, and fast‑moving consumer goods, where the Authority has publicly signalled increased scrutiny. Complainants in these sectors should prepare for accelerated information requests.

Costs, fees, and tax considerations

The TCA does not charge any filing fee to submit a complaint. However, complainants should budget for the professional and administrative costs of preparing a robust submission. The table below provides indicative ranges; actual costs depend on the complexity of the case, the volume of evidence, and whether urgent interim measures are sought.

Item	Typical amount (estimate)	Notes
TCA filing fee	None	The TCA does not charge complainants a fee.
External counsel (complaint drafting and submission)	€1,000–€10,000+	Range depends on complexity, sector, and whether interim measures are sought.
Forensic evidence collection / eDiscovery	€2,000–€50,000+	Depends on data volume and whether external vendors are needed.
Certified Turkish translations	€100–€500 per document	Key documents should be translated and certified by a sworn translator.
Expert economic report	€5,000–€100,000+	Market analyses or damages reports are case dependent; not always necessary at filing stage.

Tax treatment of any recoveries, settlements, or fines arising from a TCA investigation varies depending on the outcome and the parties’ tax residence. Complainants should consult a Turkish tax adviser on the implications of damages claims or settlement proceeds.

What changed in 2026: TCA enforcement and guidance

The first half of 2026 has seen a marked increase in the Competition Board’s enforcement activity. The TCA has issued a higher volume of preliminary inquiry decisions, and the likely practical effect is that complainants face more rigorous initial screening of their evidence packages. The Board has also signalled a willingness to impose higher fines, with several decisions in Q1–Q2 2026 setting penalties at the upper end of statutory ranges.

For complainants, the practical implication is clear: submissions filed in 2026 should include fuller evidentiary dossiers than may have been sufficient in prior years. Industry observers expect the TCA to prioritise complaints in digital markets, platform economics, and pharmaceutical distribution, sectors where the Authority has publicly indicated concern. Complainants who provide structured market data, clear competitive‑harm narratives, and well‑indexed documentary evidence are better positioned to pass the initial assessment filter and trigger a formal investigation under this heightened enforcement posture.

Common pitfalls when filing a complaint with the Turkish Competition Authority

Poor or missing evidence index. Submitting documents without a numbered index forces the TCA case team to reconstruct the narrative. Always include a cross‑referenced exhibit table.
Inconsistent witness statements. Contradictions between affidavits and documentary evidence undermine credibility. Review all statements against the factual chronology before filing.
Failure to request confidentiality. Omitting the confidentiality cover sheet means commercially sensitive data may be disclosed to the respondent during an investigation. Submit the cover sheet with every filing that contains sensitive information.
Inadequate jurisdiction explanation. Foreign company complaints that do not articulate how the alleged conduct affects the Turkish market risk dismissal at the initial assessment stage. Address the effects‑doctrine nexus explicitly.
Unverified or uncertified translations. Submitting unofficial translations of key documents may lead to TCA requests for supplementary information, delaying the process by weeks. Use sworn translators.
Missing Power of Attorney. If counsel files on behalf of the complainant and the POA is absent or incorrectly executed, the submission may be returned. Prepare and notarise the POA before filing.
Over‑redacting evidence. Removing so much information that the TCA cannot assess the merits defeats the purpose of the submission. Redact only what is genuinely confidential and provide unredacted originals under the confidentiality cover sheet.
Not preparing for possible dawn raids. A complaint about a competitor may prompt the TCA to investigate the complainant’s own sector, including through unannounced inspections. Ensure your own compliance house is in order before filing.
Poor chain of custody for digital evidence. Emails and screenshots must be preserved with metadata intact. Forensic imaging or notarised printouts strengthen evidentiary weight.
Unrealistic remedy requests. Requesting disproportionate sanctions or structural remedies without a supporting economic rationale undermines the complaint’s credibility. Frame the relief sought in line with established Board practice.

Dawn raids and searches, what to expect

If the TCA opens a full investigation, it has the power to conduct unannounced on‑site inspections (dawn raids) at the respondent’s premises, and, in some cases, at third‑party locations. Complainants should be aware that filing a complaint may indirectly expose their own operations to scrutiny if the TCA broadens its investigation to the wider market. Immediate steps upon receiving a dawn‑raid team include verifying the officials’ identification and authorisation documents, contacting counsel without delay, designating a liaison to accompany inspectors, and ensuring that privileged legal correspondence is clearly marked and separated. Companies that have not rehearsed a dawn‑raid protocol risk inadvertently disclosing privileged materials or obstructing the inspection, both of which carry serious consequences.

Need Legal Advice?

This article was produced by Global Law Experts. For specialist advice on this topic, contact Efser Zeynep Ergun at ZESA Attorney Partnership, a member of the Global Law Experts network.

Sources

FAQs

How do I file a complaint with the Turkish Competition Authority (TCA)?

Prepare a signed complaint letter with a detailed factual chronology, an evidence index referencing numbered exhibits, and a legal analysis identifying the relevant articles of Act No. 4054. Submit the package through the Rekabet Kurumu’s online complaint notice system or by post to the Authority’s Ankara headquarters. There is no mandatory complaint form and no filing fee.

What information and documents must be included in a TCA complaint?

At a minimum, include a signed cover letter, a detailed statement of facts, an evidence index, supporting documentary evidence (contracts, emails, invoices), corporate identification documents, and, if counsel is filing, a notarised Power of Attorney. Market data and certified Turkish translations of non‑Turkish documents significantly strengthen the submission.

Can a foreign company or individual submit a complaint to the TCA?

Yes. The TCA applies an effects‑based jurisdiction test: any conduct that distorts competition within Turkey is subject to its authority, regardless of where the parties are incorporated. Foreign complainants should include a jurisdictional analysis explaining the Turkish market impact, provide notarised corporate documents with apostille, and ensure all key evidence is accompanied by certified Turkish translations.

How long does the TCA take to decide whether to open an investigation after a complaint?

The initial assessment typically takes 30–90 days, though this range is a matter of established practice rather than a fixed statutory deadline. Complex cases or those requiring supplementary information may take longer. The Competition Board’s decision to open a preliminary inquiry or full investigation generally follows within 1–4 months of receipt. The investigation start time also depends on the TCA’s current caseload and enforcement priorities.

Can I submit an anonymous or confidential complaint?

You may request confidential treatment of your identity and commercially sensitive information by attaching a confidentiality cover sheet and justification memo. The TCA assesses these requests case by case. A fully anonymous complaint, where even the TCA does not know the complainant’s identity, is possible but may limit the Authority’s ability to seek clarification or additional evidence, potentially weakening the complaint’s prospects.

When should I hire counsel to file a TCA complaint?

Engage experienced antitrust counsel before filing if: the matter involves complex economic evidence or market definition; you are a foreign entity unfamiliar with Turkish procedural requirements; there is a risk of retaliatory dawn raids; you intend to seek interim measures; or the complaint involves cross‑border conduct requiring a jurisdictional analysis. Early legal involvement improves the quality of the submission and reduces the risk of procedural delays.