Introduction

Acquiring a company in Europe is subject to European and national competition authorities' (NCAs) approval. When a transaction meets specific jurisdictional thresholds, the merging parties are required to notify the competent authority. However, if those thresholds are not met, notification is not mandatory, allowing mergers to proceed without regulatory scrutiny.

These thresholds are designed to focus enforcement resources on potentially problematic mergers. Nonetheless, authorities are increasingly interested in reviewing below-threshold mergers that do not meet the jurisdictional threshold for mandatory notification over concerns that some mergers could pose competition risks in local and national markets.

Against this backdrop, several Member States have empowered their NCAs to scrutinise below-threshold mergers through “call-in” mechanisms[1]. The Netherlands[2] and France[3] are currently considering such a policy. Under this approach, NCAs can request a notification from the merging parties when specific criteria are met. However, NCAs retain broad discretion in exercising this power, raising concerns about effectiveness, predictability and legal uncertainty for the merging parties. Firms may face increased legal costs, delays in deal closing, and even potential behavioural and structural remedies when the merger is completed before a call-in request is issued.

Despite these concerns, the European Commission encourages Member States to adopt and use call-in powers[4]. It further advocates using these powers with the referral mechanism under EU law, allowing NCAs to refer transactions to the Commission for review, even when the mergers do not meet EU jurisdictional thresholds. This allows the Commission to oversee below-threshold transactions without revising existing EU merger law.

The Commission has already applied this strategy. It accepted a referral from the Italian Competition Authority, invoking its national call-in power, to review the Nvidia/Run:ai merger[5]. While the Commission ultimately cleared the deal, the merging parties have challenged its jurisdiction before the Court of Justice[6].

This paper assesses the use of call-in mechanisms across the EU and their interaction with the referral procedure at the European level. It concludes with policy recommendations for national authorities and the Commission on how to structure and apply call-in powers in line with objectives of effectiveness, predictability, and legal certainty.

Call-in Power Mechanisms in EU Jurisdictions

Several EU Member States, including Denmark, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Norway, Slovenia, and Sweden, have implemented call-in powers. The Netherlands is currently considering a similar reform.

The comparative assessment shows that call-in mechanisms typically include four core elements: (1) a quantitative threshold, (2) a competition-based substantive test, (3) the option for voluntary notification, and (4) a defined timeframe within which the NCA must exercise its powers.

As illustrated in Figure 1 and detailed in Annex 1, most jurisdictions, except Ireland, Lithuania, Norway, and the Netherlands, rely on a quantitative threshold. These thresholds provide merging parties with a clearer and more predictable understanding of where and when a transaction may be subject to review. In most cases, the thresholds require a domestic presence based on turnover or market share, ensuring a local nexus. Turnover-based thresholds offer greater clarity and ease of application, as firms typically have this information readily available. By contrast, thresholds based on market share are more complex and burdensome, as they require merging parties to define the relevant product and geographic markets.

All countries, except Slovenia and Sweden, apply a competition-based substantive test, which assesses whether the merger may impede effective competition by creating or strengthening a dominant position or significantly reducing competition.

To reduce legal uncertainty, all jurisdictions except Denmark allow merging parties to voluntarily notify a transaction. This allows firms to engage with the NCA proactively and seek legal certainty. However, this mechanism places the burden on companies to self-assess and notify any potential call-in cases. As a result, it increases transaction costs and delays for merging parties and adds to the administrative workload of NCAs.

An NCA may invoke its call-in power either following voluntary notification or based on information from the merging parties, third parties, or public sources, but only within a legally defined timeframe (see Annex 1).

Finally, several jurisdictions, including Denmark, Hungary, Ireland, and Italy, have issued guidance to assist merging parties in assessing the likelihood of a call-in. Such guidance enhances transparency and reduces uncertainty by clarifying how an NCA applies discretion.

As shown in Table 1, the actual use of call-in powers has remained limited across most jurisdictions, with notable exceptions in Italy, Norway, and Sweden. To date, only one case, Italy’s Nvidia/Run:ai, has been referred to the Commission. This suggests that call-in powers are primarily being used to address domestic competition concerns rather than to fill gaps in enforcement at the EU level.

Table 1: Call-in power usage in EU Jurisdictions

Source: Digital Competition from Darach Connolly et al. (2025).

Interactions Between Call-in Power Mechanisms and Referral Mechanisms

Call-in and referral mechanisms serve distinct yet complementary functions within the EU merger control framework. Call-in powers allow NCAs to request notifications for mergers that fall below national jurisdictional thresholds. In contrast, Article 22 of the EU Merger Regulation (EUMR) enables NCAs to refer transactions to the Commission, provided the merger affects trade between Member States.

In practice, referrals under Article 22 remain rare. Between 1990 and 2025, out of 9,590 notified cases, the Commission received only 52 referral requests from NCAs under Article 22 EUMR[8]. Figure 2 below illustrates that the Commission receives fewer than four NCA referrals annually, a trend that has remained relatively stable over time. This low frequency indicates that Article 22 is invoked only in exceptional cases.

Source: Digital Competition from data from the European Commission.

The Commission has encouraged broader use of Article 22 to address perceived gaps in EU merger enforcement. Notably, it began accepting referral requests even from NCAs that lacked jurisdiction to review the transaction under national law[9]. However, the Court of Justice in the Illumina v Commission judgment significantly curtailed this expansive interpretation. The Court held that referral requests under Article 22 must be based on transactions that meet the national jurisdictional thresholds, citing the need to guarantee effectiveness, predictability, and legal certainty for the merging parties[10].

In response, the Commission has called on Member States with call-in powers to refer relevant cases. The Nvidia/Run:ai referral from Italy is the first instance of such coordination. While the Commission unconditionally cleared the merger, the referral is challenged before the Court of Justice. The merging parties argue that the Commission’s referral acceptance infringed key legal principles, including institutional balance, legal certainty, proportionality, and equal treatment.

Although the Court’s ruling in this case is still pending, the Illumina judgment provides crucial guidance. It reaffirms that jurisdictional thresholds are of cardinal importance for ensuring that merging parties can reliably determine whether a transaction is subject to merger review[11]. In particular, turnover-based thresholds are seen as a cornerstone of foreseeability and legal certainty. The merging parties must be able to identify the competent authority, applicable deadlines, and notification procedures with clarity and speed[12].

Against this backdrop, the operation of Article 22 must align with the principles of effectiveness, predictability, and legal certainty. While most national call-in regimes feature clear thresholds and time limits, their reliance on NCA discretion ultimately introduces uncertainty. Unless a transaction is voluntarily notified, merging parties cannot reliably anticipate whether a review will be triggered. Yet, as the Court has noted, informal notifications are inconsistent with the effectiveness objective[13]. This raises doubts about whether the Commission can lawfully accept referrals from call-in mechanisms.

Recommendations

Given potential competition concerns, the desire to review below-threshold mergers is legitimate. However, any such regime must ensure effectiveness, predictability, and legal certainty for the merging parties.

For national policymakers, call-in mechanisms should Include objective thresholds, preferably based on turnover and with a clear local nexus, provide a defined timeframe within which the NCA can act, allow voluntary notification to give firms an avenue to seek legal clarity and be supported by clear guidance outlining both quantitative and qualitative elements for a clear and cost-effective assessment.

For the Commission, referral requests should only be accepted when they originate from NCAs operating within such frameworks. This ensures consistency with the principles of effectiveness, predictability, and legal certainty articulated in the Illumina judgment.

Annexe

Annex 1: Call-in power conditions in EU Jurisdictions

Source: Digital Competition based on data from the footnotes.

[1] Christophe Carugati, How Should Europe Revamp Merger Policy for Non-Notifiable Deals?, Digital Competition, 24 September 2024 (accessed 8 April 2025). Available at: https://www.digital-competition.com/comment/how-should-europe-revamp-merger-policy-for-non-notifiable-deals%3F

[2] Jochem de Kok et al, Legislative Proposal Empowers Dutch Competition Authority to Review Below-Threshold Transactions, A&O Sherman, 20 March 2025 (accessed 8 April 2025). Available at: https://blog.allenovery.com/aoblog/corporate_nl/legislative-proposal-empowers-dutch-competition-authority-to-review-below-threshold-transactions

[3] Autorité de la concurrence, Mergers Below the Control Thresholds : Following the Public Consultation, The Autorité is Continuing its Work to Propose a Reform Ensuring Effective Control, 10 April 2025 (accessed 15 April 2025). Available at: https://www.autoritedelaconcurrence.fr/en/article/mergers-below-control-thresholds-following-public-consultation-autorite-continuing-its-work

[4] Francesca McClimont, Ribera: Killer Acquisitions Still A Key Concern, GCR, 4 April 2025 (accessed 8 April 2025). Available at: https://globalcompetitionreview.com/article/ribera-killer-acquisitions-still-key-concern

[5] European Commission, Commission Approves Acquisition of Run:ai by NVIDIA, 20 December 2024 (accessed 8 April 2025). Available at: https://ec.europa.eu/commission/presscorner/detail/en/ip_24_6548

[6] T-15/25 Nvidia v Commission, 10 January 2025.

[7] Darach Connolly et al, Predictably Uncertain: Managing Merger Control Call-In Risk at Local Level in the EU, Kluwer Competition Law Blog, 1st April 2025 (accessed 9 April 2025). Available at: https://competitionlawblog.kluwercompetitionlaw.com/2025/04/01/predictably-uncertain-managing-merger-control-call-in-risk-at-local-level-in-the-eu/

[8] European Commission, Statistics on Mergers Cases (accessed 9 April 2025). Available at: https://competition-policy.ec.europa.eu/mergers/statistics_en

[9] Communication From the Commission Guidance on the Application of the Referral Mechanism Set Out in Article 22 of the Merger Regulation to Certain Categories of Cases 2021/C 113/01.

[10] C-611/22 P Illumina v Commission, ECLI:EU:C:2024:264, 3 September 2024, para. 206.

[11] Ibid, para. 208.

[12] Ibid, para. 209.

[13] Ibid, para. 209.

[14] Christian Bergqvist and Mark Gall, Significant Amendments to the Danish Competition Act, Kluwer Competition Law Blog, 5 June 2024 (accessed 8 April 2025). Available at: https://competitionlawblog.kluwercompetitionlaw.com/2024/06/05/significant-amendments-to-the-danish-competition-act/

[15] Anikó Keller et al, Hungary, Mergerfilers, (accessed 8 April 2025). Available at: https://www.mergerfilers.com/guide.aspx?expertjuris=Hungary#guidebook

[16] Halldór Karl Halldórsson and Þorbjörg Ásta Leifsdóttir, Iceland, Mergerfilers, (accessed 8 April 2025). Available at: https://www.mergerfilers.com/guide.aspx?expertjuris=Iceland#guidebook

[17] Dervla Broderick and Ruchit Patel, Ireland introduces enhanced merger control powers, Ropes & Gray, 29 August 2023 (accessed 8 April 2025). Available at: https://www.ropesgray.com/en/insights/viewpoints/102imsf/ireland-introduces-enhanced-merger-control-powers

[18] Legance, The Italian Competition Authority’s New Powers Concerning Mergers Below the Threshold, January 2023 (accessed 9 April 2025). Available at: https://www.legance.com/the-italian-competition-authoritys-new-powers-concerning-mergers-below-the-threshold/

[19] Lina Darulienė et al, Lithuania, Mergerfilers (accessed 9 April 2025). Available at: https://mergerfilers.com/guide.aspx?expertjuris=Lithuania#guidebook

[20] Darach Connolly et al, Predictably Uncertain: Managing Merger Control Call-In Risk at Local Level in The EU, Kluwer Competition Law Blog, 1st April 2025 (accessed 9 April 2025).

[21] Siri Teigum et al, Norway, Mergerfilers (accessed 9 April 2025). Available at: https://mergerfilers.com/guide.aspx?expertjuris=Norway#guidebook

[22] Tomaž Lukman et al, Slovenia, Mergerfilers (accessed 9 April 2025). Available at: https://mergerfilers.com/guide.aspx?expertjuris=Slovenia#guidebook

[23] Erik Söderlind et al, Sweden, Mergerfilers (accessed 9 April 2025). Available at: https://mergerfilers.com/guide.aspx?expertjuris=Sweden#guidebook