Form CO


Author Definition



The European Commission must review and clear, before their implementation, mergers, acquisitions of control and certain types of newly formed joint-ventures (“concentrations”) that meet the turnover thresholds set out in Regulation No 139/2004 (“the Merger Regulation”). The so-called Form CO, appended to Regulation No 802/2004 implementing the Merger Regulation (“the Implementing Regulation”), sets out the information that must be submitted to the Commission upon notification of such a proposed concentration as well as the structure and order of presentation the notifying parties must follow when furnishing the said information. The information pertains to the transaction, the parties thereto, the markets on which they operate and their specificities as well as alleged efficiencies. The prescribed time limits for the Commission’s review only begin to run once the information required by the Form CO is deemed complete.



In line with most jurisdictions throughout the world in which a merger control regime exists (see, in this respect, the ICN’s Merger Notification and Procedures Template), the European Union requires the notification of contemplated concentrations that fall under its purview prior to their implementation and sets out a detailed list of compulsory information in this context.

Even if, for the purposes of establishing the Commission’s jurisdiction in particularly complex cases, the notification may contain ample developments on the transaction underpinning the change of control (Section 3 of Form CO) or even on the turnover to be taken into account with regard to the applicable jurisdictional thresholds (Section 4), the bulk of the information submitted will normally relate to the markets on which the concentration may have an impact. In this regard, the information sought by the Commission covers both static and dynamic dimensions of competition (see Section 7: market size, market shares of parties to the concentration and competitors, capacities; Section 8: structure of supply and demand, product differentiation and closeness of competition, market entry and exit, R&D, cooperative agreements).

Qualification of the relevant market as an “affected” market triggers the obligation to submit the information prescribed under Sections 7 and 8. The thresholds for qualifying as an affected market were revisited by the Commission as part of a simplification package, which entered into force on 1 January 2014. The combined market share threshold of the parties post-transaction on the same relevant market (horizontal overlap) increased from 15% to 20%, whereas, in case of vertical relationships, the combined market share threshold in any of the upstream or downstream markets increased from 25% to 30%. These market share thresholds are, broadly speaking, reflected in Member States’ own merger control regimes (see the EU Merger Working Group’s Report on Merger Information Requirements, table B – part 3) and recent changes brought at national level have sought, where applicable, to close the gap with the Commission’s own requirements as reflected in Form CO (see, e.g., in France Decree n°2019-339 of 18 April 2019 which raises the vertical threshold from 25% to 30%). Form CO also contemplates the provision of the information prescribed under Sections 7 and 8 in relation to “other markets” where, in the absence of overlaps, other concerns may be flagged in relation to potential competition or conglomeral effects (see Section 6.4).

In keeping with the objective of avoiding undue administrative burdens on notifying parties and seeking information only to the extent necessary to address material competitive concerns (see, in this regard, ICN Recommended Practices for Merger Notification and Procedures, part V), the Commission employs a number of tools to mitigate, where appropriate, the obligations weighing on notifying parties. Thus, on the one hand, it may waive the obligation to provide a number of information otherwise prescribed by the Form CO. Interestingly, the scope of potential waivers appears to be relatively large and includes the obligation to provide internal documents prepared for assessing the rationale of the concentration or competitive conditions on the affected markets – even as, arguably, the provision of the said documents entails, on the part of the parties, no drafting efforts and comparatively limited investigatory efforts. On the other hand, provided certain conditions are fulfilled, notifying parties may only have to provide the more limited information required under the so-called Short Form CO, also appended to the Implementing Regulation. Eligibility conditions vary in nature (see para. 5 of the Commission Notice on a Simplified Procedure) and relate (i) to the absence of horizontal and vertical relationships with regard to any markets on which the parties are present, (ii) their limited combined market share on markets thus concerned, (iii) the acquisition of sole control of an undertaking by a party which already exerts joint control over the former or (iv) the acquisition of a joint venture with negligible activities within the EEA.

The simplification package adjusted the market share thresholds applicable under (ii) in a manner consistent with those applicable to “affected markets” under Form CO (see above) while introducing a new category whereby parties in a horizontal relationship with a combined market share not exceeding 50% and a Herfindahl-Hirschman Index increment not exceeding 150 “may” also benefit from the simplified procedure. In other words, in the latter instance, the Commission retains greater discretion to award the benefit of the simplified procedure, to be discussed with parties at the informal pre-notification stage.

Variations in scope of the simplified procedure witnessed in different jurisdictions may reflect competition authorities’ different sensitivities to specific theories of harm. For instance, in France until 2020, a change from joint to sole control exerted by the same undertaking did not render the transaction eligible to a simplified procedure, and has even attracted in-depth investigations and the imposition of substantial remedies (see Decision 13-DCC-90, Casino/Monoprix).

Further avenues for simplification, such as exempting certain categories of cases from notification or providing for a self-assessment system combined with voluntary notification (such as exists, for instance, in the United Kingdom), were considered by the Commission in a 2014 White paper and then again in the context of a public consultation in 2017 but have been shelved, at least for the time being, due to somewhat lackluster response (see Commission SWD Evaluation of procedural and jurisdictional aspects of EU Merger control, March 2021). Finally, the omission to notify a concentration, whether through a Form CO or a Short Form, or failure to provide complete information, entails significant legal consequences. Indeed, the Commission has been keen in recent years to ramp its use of fines for procedural infringements, in keeping with Article 14 of the Merger Regulation. The Altice/PT and Canon/Toshiba decisions thus take issue with the fact that the concerned concentrations were implemented in breach of the standstill clause (Article 7 of the Merger Regulation) as well as, at least in part, before notification. The Facebook/Whatsapp and GE/LM Wind Power Holding fine the notifying parties for providing incorrect information in their notification, respectively 110 and 52 million Euros.



Bailly, M., Malamataris, C. Procedural developments in EU merger control. ERA Forum 21, 251–265 (2020)

Dave Anderson, Paul Culliford, "Surveying the surveys – The drive for implementation of the ICN’s recommended practices for merger notification and review procedures", Concurrences N° 3-2020, Art. N° 95408

This article is being reviewed by the Editors of the Dictionary.


  • European Court of Justice (Luxembourg)


David Viros, Form CO, Global Dictionary of Competition Law, Concurrences, Art. N° 12260

Visites 2040

Publisher Concurrences

Date 1 January 1900

Number of pages 500


Institution Definition

Form which companies must use where a planned concentration has a Community dimension within the meaning of the Merger Regulation and therefore has to be notified to the Commission. Form CO explains in detail how notifications of concentrations must be submitted and what information and supporting documentation must be provided to the Commission.

© European Commission