1. Meaning of Trustee Monitoring

In competition law, trustee monitoring refers to the use of an independent person or professional firm to supervise whether a company is properly complying with commitments, remedies, interim measures, or other obligations imposed or accepted during a merger or antitrust proceeding.

The trustee effectively provides an independent layer of supervision between the competition authority and the undertaking. Competition authorities often describe a monitoring trustee as their “eyes and ears”, particularly where compliance requires continuous observation that the authority cannot practically perform itself.

Trustee monitoring is especially important where a transaction has been approved subject to conditions such as:

• divestiture of part of a business;
• keeping two businesses separate before divestiture;
• preserving the viability of assets that must be sold;
• granting competitors access to infrastructure, technology, data, or intellectual property;
• maintaining supply relationships;
• preventing discrimination against competitors;
• complying with interoperability requirements; or
• implementing complex behavioural commitments.

Thus, the trustee normally does not replace the competition authority. The authority retains responsibility for enforcement, while the trustee gathers information, supervises implementation and reports problems.

2. Why Trustee Monitoring Is Necessary

Competition remedies can remain effective only if the companies actually implement them. A written commitment may appear sufficient when a merger is approved but prove ineffective if implementation is delayed or interpreted narrowly.

Consider a merger where Company A agrees to sell one of its factories. Between approval of the merger and completion of the sale, Company A might reduce investment in the factory, transfer important employees elsewhere or allow customer relationships to deteriorate.

Even though the factory is eventually sold, the purchaser could receive a substantially weakened business.

A monitoring trustee can supervise the business during this period and report whether its competitiveness and commercial viability are being preserved.

Trustees are therefore particularly useful where remedies require continuous supervision rather than a single act of compliance.

3. Independence of the Trustee

Independence is one of the most important characteristics of trustee monitoring.

A trustee should normally:

1. be independent from the merging companies;
2. possess appropriate professional and technical expertise;
3. have sufficient personnel and resources;
4. avoid financial or professional conflicts of interest;
5. have adequate access to relevant information;
6. report objectively to the competition authority.

The FTC's merger-remedies guidance similarly explains that monitors should have appropriate expertise and no financial or other conflicting relationship with the parties or purchaser.

Although the companies may pay the trustee's fees, the trustee's monitoring responsibilities are ultimately directed toward ensuring compliance with the authority's order or commitments.

4. Principal Functions of a Monitoring Trustee

Monitoring Compliance

The trustee examines whether the company is complying with every relevant commitment.

This can involve reviewing contracts, financial records, management decisions, customer arrangements, technical systems and internal policies.

Preserving a Divestment Business

Where assets must eventually be sold, the trustee can supervise whether the business remains commercially viable until the purchaser takes control.

This may include monitoring:

• staffing;
• investment;
• customer retention;
• inventories;
• intellectual property;
• financial resources; and
• management independence.

Hold-Separate Monitoring

Competition authorities sometimes require businesses to remain operationally separate during an investigation or divestiture process.

The trustee may check whether commercially sensitive information is being improperly exchanged or whether the acquiring company is exercising prohibited influence over the target.

The UK's CMA, for example, directed the appointment of a monitoring trustee in its GXO/Wincanton investigation under interim enforcement arrangements.

Monitoring Behavioural Remedies

Behavioural commitments can require monitoring for several years.

Examples include commitments relating to:

• non-discriminatory access;
• interoperability;
• supply obligations;
• licensing;
• data separation;
• pricing procedures;
• platform access; and
• dealings with competitors.

Receiving Third-Party Complaints

Competitors, customers and suppliers may sometimes communicate concerns to the trustee.

This is particularly useful because these market participants may be the first parties to notice that a commitment is not operating properly.

Reporting

The trustee normally submits periodic reports to the competition authority.

Reports can identify:

• compliance achieved;
• outstanding obligations;
• implementation difficulties;
• possible breaches;
• third-party complaints; and
• recommended corrective measures.

5. Monitoring Trustee vs Divestiture Trustee

These concepts should not be confused.

A monitoring trustee primarily supervises implementation and reports whether the parties are complying.

A divestiture trustee, by contrast, may receive authority to carry out the sale of assets when the company itself has failed to complete an agreed divestiture within the required period.

The same professional may sometimes perform both functions, depending upon the relevant remedy framework, but legally the functions are different.

6. Trustee Monitoring and Structural Remedies

Structural remedies normally involve changes to the ownership or structure of businesses.

The most common example is divestiture.

Suppose:

Company X + Company Y = excessive concentration

The authority may approve the transaction provided Company X sells Business Z.

Trustee monitoring may then cover the entire period between the authority's decision and completion of the divestiture.

The trustee can supervise whether Business Z remains:

viable + independent + competitive + saleable.

This prevents the divested business from becoming merely an empty collection of assets incapable of competing effectively.

7. Trustee Monitoring and Behavioural Remedies

Trustee monitoring can become even more important with behavioural remedies.

For example, a vertically integrated company might promise to provide competitors with access to essential technology on equal terms.

The trustee could examine:

• requests for access;
• response times;
• technical conditions;
• contractual terms;
• complaints;
• differences between internal and external treatment.

This helps detect subtle discrimination that might otherwise be difficult for the authority to observe.

8. Important Case Laws and Competition Decisions

1. Microsoft Corp. v Commission — Case T-201/04

This is one of the most important judicial decisions concerning an independent monitoring trustee.

The European Commission had found Microsoft responsible for abuses relating to interoperability information and the tying of Windows Media Player.

The remedial mechanism included an independent monitoring trustee with extensive access rights.

Microsoft challenged various aspects of the Commission's decision.

The General Court upheld the principal substantive infringement findings but annulled the portion of the decision requiring Microsoft to submit to a monitoring mechanism that effectively gave the trustee powers independent of the Commission and required Microsoft to bear all associated costs.

The judgment therefore establishes an important principle:

A monitoring mechanism must remain within the legal powers available to the competition authority.

Trustee monitoring cannot become an unlawful delegation of the authority's enforcement responsibility.

2. Google/Fitbit — Case M.9660

Google's acquisition of Fitbit raised competition concerns involving health and fitness data, digital advertising and access to Fitbit's ecosystem.

The European Commission cleared the transaction subject to commitments.

The remedy framework included extensive monitoring arrangements. Published analysis of the decision describes trustee responsibilities involving auditing, reporting, technical verification, data-separation measures and consideration of certain changes to relevant terms and conditions.

This case demonstrates why trustee monitoring is increasingly important in digital markets.

Traditional monitoring may involve physical factories and inventories.

Digital monitoring can instead involve:

data flows + APIs + access logs + technical architecture + algorithms + contractual conditions.

3. Daimler/BMW — Case M.8744

The Daimler/BMW joint venture concerning mobility services provides another example of monitoring associated with behavioural commitments.

The European Commission accepted commitments addressing competition concerns arising from the combination.

Published analysis of the monitoring arrangements explains that the trustee could monitor compliance, deal with third-party requests, propose measures necessary for compliance and report potential failures to the Commission.

This illustrates another important function:

trustees can provide an accessible compliance channel for affected market participants.

4. Anadolu Endüstri Holding/Migros

The Turkish Competition Authority examined the acquisition of Migros in circumstances involving links between the acquiring group and significant beverage businesses.

Commitments were imposed to address concerns about the treatment of competing suppliers.

Among other matters, the commitments concerned maintaining commercial relationships with competitors and avoiding interference with competitors' products.

A monitoring trustee was included for supervision of the commitments for the relevant period.

The case demonstrates the usefulness of trustee monitoring where the concern involves vertical relationships and potential discrimination against rival suppliers.

5. Tesco/Migros

The Turkish Tesco/Migros transaction also involved trustee monitoring.

The existing trustee arrangements associated with earlier Migros commitments were extended or revised so that monitoring could cover relevant obligations arising from the additional transaction.

Reporting arrangements included periodic reporting to the Turkish Competition Board.

The decision illustrates how monitoring mechanisms can sometimes be adapted when later transactions affect an already-remedied market structure.

6. EssilorLuxottica/GrandVision

The acquisition of optical retailer GrandVision by EssilorLuxottica raised vertical competition concerns because EssilorLuxottica had significant activities at different levels of the optical supply chain.

The Turkish Competition Authority subjected the transaction to behavioural commitments for a defined period, with the possibility of extension under specified circumstances.

Monitoring arrangements were incorporated into the remedy structure.

The case demonstrates why trustees can be particularly useful in vertical mergers.

The relevant problem is not necessarily elimination of a direct competitor. Instead, authorities may be concerned that the merged business could disadvantage downstream or upstream competitors.

Continuous monitoring can therefore become necessary.

7. GXO Logistics/Wincanton

The UK Competition and Markets Authority's investigation of GXO Logistics' acquisition of Wincanton provides a recent UK example.

During the merger investigation, the CMA issued directions requiring the appointment of a monitoring trustee under its interim enforcement framework.

The purpose of such interim arrangements is to help ensure that businesses remain appropriately separate and that competitive conditions are not irreversibly altered while merger review continues.

This illustrates an important distinction:

trustee monitoring is not limited to final merger remedies.

It can also operate during the investigation itself.

8. Aramark/Entier

The CMA's Aramark/Entier merger investigation provides another recent illustration.

In November 2025, the CMA directed Aramark and Entier to appoint a monitoring trustee pursuant to an initial enforcement order. The CMA subsequently published its final report in January 2026.

Again, monitoring served an interim enforcement function rather than merely supervising a long-term post-merger behavioural remedy.

9. Main Competition Concerns Addressed by Trustee Monitoring

Trustee monitoring can help address several different risks.

Asset deterioration: A company required to divest a business may have little incentive to invest in that business before selling it.

Information exchange: During merger proceedings, competing businesses might improperly exchange commercially sensitive information.

Discriminatory conduct: A vertically integrated company could theoretically provide competitors with inferior access or conditions.

Delay: Companies may delay implementing difficult remedies.

Technical non-compliance: Digital commitments involving APIs, data separation or interoperability may be impossible to evaluate from contractual documents alone.

Remedy circumvention: A company could comply formally with the wording of a commitment while undermining its commercial purpose.

Independent monitoring helps authorities detect these problems earlier.

10. Limits of Trustee Monitoring

Trustee monitoring is not automatically effective.

Its effectiveness depends heavily on the trustee's:

independence, expertise, investigative access, resources, reporting obligations and clearly defined mandate.

Complex digital remedies can be particularly difficult because understanding compliance may require specialist knowledge of software, data architecture, algorithms or cybersecurity.

Monitoring can also become expensive where commitments remain effective for many years.

Finally, as Microsoft v Commission demonstrates, the trustee must not simply become an independent regulator operating outside the authority's lawful institutional framework.

11. Practical Monitoring Structure

A typical arrangement can be represented as:

Competition Authority → Independent Trustee → Company → Compliance Information → Trustee Report → Competition Authority

The company remains legally responsible for complying with the commitments.

The trustee observes and verifies.

The competition authority ultimately decides whether enforcement action is necessary.

12. Importance in Modern Competition Law

Trustee monitoring has become particularly valuable because competition remedies are increasingly technically complicated.

Modern cases can involve:

platform access → interoperability → data separation → licensing → algorithms → digital ecosystems → infrastructure access → long-term supply commitments.

A competition authority may lack the resources to continuously inspect all these matters itself.

Independent trustees therefore provide specialized and continuous supervision while leaving ultimate enforcement responsibility with the authority.

Conclusion

Trustee monitoring is an enforcement-support mechanism designed to make competition remedies effective in practice rather than merely on paper. An independent trustee can supervise divestitures, hold-separate obligations, behavioural commitments, data-access requirements and other remedies, receive third-party concerns and report compliance problems to the competition authority.