How to Respond to a CMA Market Study: a Step‑by‑step Guide for Businesses (2026 Update)

When the Competition and Markets Authority (CMA) announces a market study, or sends your business an information request, the clock starts immediately, and the quality of your initial response shapes every stage that follows. Understanding how to respond to a CMA market study is essential for general counsel, compliance teams and senior executives who need a structured, defensible workflow rather than ad‑hoc reactions. The Enterprise Act 2002 gives the CMA broad powers to compel the production of documents and data, and the CMA’s early‑2026 guidance signals material changes to the way it expects firms to engage, including the introduction of project roadmaps, clearer information‑request formats and earlier remedies conversations.

This guide sets out the complete CMA market study process, from the moment you learn a study has been launched through document production, privilege handling and post‑production cooperation, updated to reflect the 2026 procedural reforms.

Overview of the CMA Market Study Process and Who It Applies To

What is a market study?

A CMA market study is a formal examination of whether competition in a particular market is working well for consumers. The CMA derives its authority to conduct market studies from Part 4 of the Enterprise Act 2002, supplemented by its own published guidance, Market Studies and Market Investigations: Supplemental Guidance on the CMA’s Approach. A market study differs from a full market investigation: the study is the initial, typically less intrusive phase in which the CMA gathers evidence and consults stakeholders. If the CMA concludes that features of the market prevent, restrict or distort competition, it may make a market investigation reference (MIR), escalating the matter into a more detailed Phase 2 investigation with legally binding remedies powers.

When will the CMA open a market study?

Common triggers include a super‑complaint made by a designated consumer body (to which the CMA must publish a reasoned response within 90 days under section 11 of the Enterprise Act 2002), a referral from a sector regulator, a government request, or the CMA’s own monitoring of markets through complaints data, price analysis or intelligence‑sharing with international competition authorities. The CMA publishes a statement of scope when a study opens, identifying the markets and issues under review and inviting interested parties to submit evidence.

Who within the business must be involved?

Any firm that operates in the market under review, whether as a supplier, purchaser, intermediary or trade association, may receive a CMA information request. Overseas parent companies with UK subsidiaries are within scope if they supply goods or services in the UK market. From the outset, the response effort should involve in‑house legal counsel (as Response Lead), IT, compliance, finance and at least one senior executive with authority to approve productions and attend CMA meetings.

Eligibility and Prerequisites for Responding to a CMA Market Study

Who is in scope?

The CMA can direct information requests at any person or business it considers relevant. This includes direct market participants (suppliers and purchasers), trade associations, professional bodies, customer groups and, critically, non‑UK companies that supply goods or services into the UK market or whose conduct has effects within the UK. If your business has a UK subsidiary, branch or significant customer base, you should assume you may be within scope.

Data and system access prerequisites

Before a formal request arrives, the Response Lead should confirm that the business has the following readiness elements in place:

• Custodian list. A pre‑identified list of individuals whose files and communications are likely to be responsive, typically senior management, commercial leads, pricing analysts and marketing decision‑makers.
• Data map. A record of where relevant electronic data resides: email servers, document management systems, shared drives, CRM platforms and financial reporting tools.
• Litigation hold capability. A documented process for issuing a preservation notice to all custodians and IT administrators, halting routine deletion of potentially responsive data.
• Privilege framework. An agreed protocol, ideally reviewed by external competition counsel, for identifying and logging legally privileged material before any production.

Engaging specialist external counsel at this stage, rather than after the request is received, significantly reduces the risk of inadvertent privilege waiver and accelerates every downstream step in the CMA market study process.

How to Respond to a CMA Market Study: Step‑by‑Step Procedure

The following procedure maps the typical workflow for responding to a CMA information request within a market study. The timeline table below summarises each step, the responsible owner and the typical duration. Individual deadlines vary: the CMA specifies a response date in each information request, and businesses should work backwards from that date to build their internal schedule.

Step 1, Immediate triage and evidence preservation (0–48 hours)

Within the first 48 hours of learning that a market study has been opened, the Response Lead should take the following actions:

1. Confirm the scope of the study by reviewing the CMA’s published statement of scope and, if an information request has been received, the specific categories of documents and data requested.
2. Issue a written litigation hold to all potential custodians and IT administrators, instructing them to suspend routine deletion of emails, documents, instant messages and transactional data falling within the scope of the study.
3. Designate a single Response Lead with decision‑making authority, supported by named representatives from IT, compliance and finance.
4. Brief the board or executive committee on the study, including preliminary scope assessment, estimated resource requirements and the statutory consequences of non‑compliance with a compulsory information request (which may include penalties under the Enterprise Act 2002).

Step 2, Review the CMA information request and map custodians (days 1–7)

Once the information request is in hand, the Response Lead and external counsel should:

1. Parse each numbered paragraph of the request, mapping it to the internal systems, databases and custodians most likely to hold responsive material.
2. Estimate the volume of potentially responsive documents and identify any categories that will require specialist collection (for example, legacy systems, archived servers or mobile‑device data).
3. Flag any requests that appear overbroad, disproportionate or ambiguous. Early engagement with the CMA case team to seek clarification or agree a proportionate scope is permissible and often welcomed, the CMA’s supplemental guidance encourages dialogue on the scope of requests.
4. Prepare a preliminary custodian list and data map to share with external counsel and the eDiscovery vendor.

Step 3, Privilege review and privilege log preparation (days 3–14)

Legal professional privilege (LPP) protects confidential communications between a client and their legal adviser made for the purpose of giving or receiving legal advice, as well as documents created for the dominant purpose of litigation. The CMA cannot compel the production of genuinely privileged material, but an improperly asserted claim will attract scrutiny and may be challenged. External counsel should:

1. Review every document flagged for potential privilege before it is included in a production set.
2. Prepare a privilege log (see the template in the Required Documents section below) that records the document ID, custodian, date, a non‑waiving description, the legal basis for the privilege claim and the number of pages withheld.
3. Apply redactions consistently, redacting only the privileged content and not the entire document where only part of the document attracts privilege.
4. Maintain a clear audit trail showing that the privilege review was conducted by or under the supervision of a qualified legal professional.

Step 4, Collect, narrow and produce documents (days 7–30+)

Document collection and production is typically the most resource‑intensive phase. Key actions include:

1. Collect electronically stored information (ESI) from identified systems using forensically defensible methods that preserve metadata (author, date created, date modified, file path).
2. De‑duplicate and apply agreed search terms or date filters to narrow the review population.
3. Conduct a first‑level relevance review (manual or technology‑assisted) to identify responsive documents, followed by a second‑level privilege review.
4. Produce documents in the format requested by the CMA, typically PDF with load files for bulk productions, or native format (Excel, CSV) for transactional data. Deliver via the CMA’s secure portal or SFTP, not by email.

Step 5, Attend CMA meetings and provide representations (weeks 2–8)

The CMA may request meetings with senior executives, site visits, or written witness statements. These interactions are an opportunity to present the business’s perspective, correct factual inaccuracies and explain the competitive context of the market. External counsel should attend all substantive meetings. Prepare witnesses with a pre‑meeting briefing that covers the scope of the study, key themes and the boundaries of what the CMA is entitled to ask. Written submissions responding to the CMA’s working papers or emerging findings should be factual, evidence‑based and linked to specific documents already produced.

Step 6, Post‑production review, ongoing cooperation and remedies dialogue (weeks 4–16)

After the initial production, the CMA will often issue follow‑up requests for additional documents, clarifications or supplementary data. Maintain the litigation hold and keep the eDiscovery platform active until the study concludes. Under the 2026 procedural changes, the CMA expects businesses to engage in earlier and more structured remedies discussions. If the CMA signals that it is considering a market investigation reference, the business should prepare a substantive remedies response that proposes practical, proportionate solutions, industry observers expect this proactive posture to carry significant weight in CMA decision‑making.

Required Documents and Information for a CMA Market Study

Documents and datasets the CMA commonly requests

The documents needed for CMA market studies vary by sector, but the following CMA evidence checklist covers the categories most frequently requested:

Document delivery formats and metadata

The CMA’s supplemental guidance expects productions to preserve document metadata (author, date created, date modified, file path, custodian). Bulk email productions should include load files in a standard format. Financial and transactional data should be provided in native format (CSV, Excel) with field descriptions. All deliveries should use the CMA’s secure upload portal or an agreed SFTP channel, unsecured email is not acceptable.

Privilege and privilege log: template and example entry

Every document withheld on grounds of legal professional privilege must be recorded in a privilege log. The log should contain sufficient detail for the CMA to assess the claim without waiving the privilege. A recommended structure is set out below:

Each entry should identify the type of privilege claimed (legal advice privilege or litigation privilege), the relationship between sender and recipient, and the nature of the communication in broad terms. If only part of a document is privileged, redact the privileged content and produce the remainder, noting the redaction in the log.

Handling third‑party and commercially sensitive data

Where the CMA requests data that includes third‑party personal data or commercially sensitive information belonging to counterparties, the producing business should apply appropriate redactions and provide a confidentiality ring proposal if necessary. The CMA’s supplemental guidance sets out the process for claiming confidentiality over specific material, including the requirement to provide a non‑confidential version for the public file.

Market Study Timeline and Key Deadlines

Statutory timelines and CMA project roadmaps

How long does a CMA market study take? There is no single statutory time limit that applies to all market studies, but the CMA’s published guidance indicates that a typical market study lasts approximately 12 months from the publication of the statement of scope to the final report. The CMA publishes a project roadmap at the outset, under the 2026 guidance changes, this roadmap is expected to be more detailed and to include indicative deadlines for each major milestone, including the consultation on provisional findings and the deadline for remedies submissions.

Where the study originates from a super‑complaint, section 11 of the Enterprise Act 2002 requires the CMA to publish its response within 90 days, though the substantive market study may continue beyond that deadline.

Recommended internal deadlines and escalation points

Businesses should not rely solely on the CMA’s deadline. A defensible internal schedule should include:

• Day 0–2. Litigation hold issued, Response Lead appointed, external counsel instructed.
• Day 1–7. Information request parsed, custodian list finalised, eDiscovery vendor engaged.
• Day 3–14. First‑pass privilege review completed, privilege log drafted.
• Day 7–30. Document collection, relevance review and first production tranche delivered.
• Week 4 onward. Ongoing cooperation, follow‑up requests, CMA meetings and representations.

If the CMA’s deadline is shorter than 30 days, which is common for targeted requests, compress the schedule accordingly and escalate resource allocation to the executive committee.

What to do if you need an extension

The CMA’s case team will generally consider reasonable, well‑evidenced requests for extensions, provided they are made early and explain the practical reasons for the delay (for example, large data volumes, legacy system access issues or the need to coordinate across multiple jurisdictions). Submit the extension request in writing, proposing a revised timeline and interim deliverables. Waiting until the deadline has passed to seek an extension is one of the most common, and most damaging, pitfalls in the CMA market study process.

Costs of Responding to a CMA Market Study

The cost of responding to a CMA information request varies significantly depending on the volume of data, the number of custodians, the complexity of privilege issues and whether specialist eDiscovery or forensic IT services are required. There are no filing fees payable to the CMA for responding to a market study. The principal cost categories are set out below.

Early scoping of the information request, including negotiating proportionate search terms and date ranges with the CMA case team, is the single most effective way to control costs.

What Changes in the CMA Market Study Process in 2026

CMA 2026 guidance, summary

In February 2026 the CMA published an update on its approach to market interventions, signalling several changes to the markets toolkit. The key developments include the introduction of more detailed project roadmaps at the start of each study, a proposal to replace the existing two‑phase (market study then market investigation) regime with a single‑phase market review tool, and an expectation that businesses will engage in structured remedies discussions earlier in the process. The CMA also indicated that information requests would be more clearly formatted and that it would publish clearer guidance on the types of evidence it considers most useful.

Practical changes to your response workflow

Businesses should update their response playbooks to reflect the following 2026 changes:

• Align your internal timeline with the CMA’s project roadmap. Request the roadmap at the outset and map your production schedule to its milestones.
• Prepare remedies proposals earlier. Under the 2026 approach, the CMA expects businesses to engage on potential remedies before provisional findings are published, not after.
• Anticipate more structured requests. The CMA’s revised guidance indicates a move toward standardised request templates with numbered categories, mirror this structure in your responses for clarity.
• Monitor for single‑phase regime legislation. If the proposal to merge market studies and market investigations into a single tool is enacted, timelines and escalation triggers will change. Industry observers expect draft legislation to be consulted on during 2026.

How to reflect 2026 changes in your privilege and production strategy

The likely practical effect of the 2026 changes is that businesses will need to conduct privilege reviews more quickly and may face compressed production deadlines. Review your privilege framework now, ensure your eDiscovery vendor can scale at short notice, and consider pre‑populating a privilege log template with standard entries that can be adapted for each request.

Common Pitfalls and How to Avoid Them When Responding to a CMA Market Study

Top pitfalls

• Late or incomplete evidence preservation. Failing to issue a litigation hold within 48 hours risks the destruction of responsive data and may constitute an offence under the Enterprise Act 2002.
• Failing to map custodians before collection. Starting collection without a clear custodian list leads to over‑collection, missed deadlines and inflated eDiscovery costs.
• Over‑producing privileged material. Producing legally privileged documents without review waives the privilege irrevocably. Every document must be reviewed before production.
• Under‑claiming privilege without a log. Withholding documents without a proper privilege log invites CMA challenges and delays.
• Insecure transfer of materials. Sending confidential or personal data via unencrypted email breaches data protection obligations and CMA expectations.
• Poor internal coordination. Without a single Response Lead and a clear RACI, tasks are duplicated, deadlines are missed and communications with the CMA are inconsistent.
• Ignoring the deadline and seeking a late extension. Requesting an extension after the deadline has passed signals non‑cooperation and damages credibility.
• Failing to engage on remedies. Under the 2026 guidance, the CMA expects proactive engagement on remedies, silence is likely to be interpreted as indifference.
• Inconsistent metadata. Stripping metadata from documents undermines the CMA’s ability to assess evidence and may trigger further requests.
• No executive oversight. Without board‑level engagement, resource allocation is inadequate and the business risks being caught off guard by escalation to a market investigation reference.

Internal RACI role map

When to escalate to external counsel

Engage specialist external competition counsel immediately if any of the following red flags are present: the information request includes questions about pricing coordination, market sharing or information exchange; the CMA signals that it is considering a market investigation reference; the business has previously been the subject of a CMA or European Commission investigation; or the volume and complexity of responsive data exceeds in‑house capacity. Early escalation is invariably less expensive than remediation after a misstep.

Conclusion

Knowing how to respond to a CMA market study is a practical, operational discipline, not a theoretical exercise. The immediate priorities are issuing a litigation hold, appointing a Response Lead, engaging external counsel and mapping custodians against the CMA’s information request. From there, a structured privilege review, defensible document production and proactive engagement on remedies position the business to manage the study effectively and minimise the risk of escalation. With the 2026 procedural reforms introducing project roadmaps and earlier remedies conversations, businesses that update their response workflows now will be materially better prepared. For tailored guidance, use the Competition, United Kingdom practice area page or search the lawyer directory for UK competition specialists.

Sources

1. Competition and Markets Authority, Supplemental Guidance on Market Studies and Market Investigations
2. CMA Blog, Update on Our Approach to Market Interventions (February 3, 2026)
3. GOV.UK, Government Response to CMA Market Study into Housebuilding
4. Enterprise Act 2002
5. Lexology, Checklist: Responding to an Information Request from the CMA
6. Ashurst, Quickguide on Market Studies and Market Investigations
7. LexisNexis, UK Market Investigations Flowchart
8. Paul, Weiss, CMA Updates and Consolidates Guidance on Its Markets Regime
9. CMA Citizen Space, Consultations and Submissions Portal
10. Ofwat / CMA, Guidance on CMA Investigation Procedures