Phoning it in? Below-threshold call-in powers and the limits of jurisdictional bright lines

The expansion of below-threshold call-in powers across Europe has quietly but materially changed how merger control risk is assessed. For dealmakers and their advisors, reliance on notification thresholds as a reliable jurisdictional filter no longer holds.

Historically, the analysis followed a workable sequence. Identify where filings are required, then assess substantive risk in those jurisdictions. The first step involved navigating local nuances, but it was essentially predictable. Virtually all European Member States operated bright-line, turnover-based thresholds. Advisors could sequence their work accordingly.

That sequencing is now under real strain. Nine EU Member States have already enacted call-in legislation. A further twelve are actively considering it. In a landscape where below-threshold call-in powers are widespread, three questions must run in parallel rather than in series:

• Where do we have a mandatory filing obligation?

• Where might the transaction be called in despite falling below thresholds?

• What is the substantive risk in those jurisdictions?

The second question is no longer peripheral. Call-in powers are being exercised across healthcare, technology, and serial acquisition strategies. Jurisdictions yet to formally enact them, such France and the Netherlands, will target similar transactions. Call-in rules operate on factors that notification tests do not capture: local market concentration, the competitive significance of pipeline assets, patterns of roll-up behaviour that individually appear benign. The regulatory concern is well-documented. Authorities believe deals involving nascent competitors have slipped through the net. Call-in powers are the chosen mechanism to close that gap.

A working model

The UK's voluntary regime provides a useful reference point. Post-Brexit, it would perhaps be ironic for UK rules to be a source of influence. Practitioners familiar with UK merger work will know the CMA's broad discretion under its share of supply threshold. Advisors need an early read on market shares, used as a proxy for share of supply, to assess whether voluntary notification is advisable. That assessment is, in substance, a quantification of call-in risk.

As more jurisdictions adopt call-in regimes, quasi-voluntary processes are likely to emerge alongside existing mandatory ones. Merger parties need deal certainty and will seek to engage with authorities for comfort that a non-notified deal will not be reviewed. The European Competition Network’s Joint Statement on the implementation of call-in mechanisms explicitly recommends that these regimes be complemented by voluntary notification procedures and informal consultation mechanisms. The UK already provides a working version of this through briefing papers, by which parties can obtain a degree of non-binding comfort from the CMA without formal notification. Expect equivalents to develop elsewhere.

One further practical point deserves attention. Call-in powers are typically subject to time limits triggered by closing. Italy's regime, for example, allows the national authority to require notification within six months of closing. As more regimes come online, advisors will need to track closing-triggered clocks alongside pre-closing filing deadlines - adding another layer to deal timetable management. For context, the CMA only has four months to call in a non-notified deal.

The operational tension

Notifiability analysis is typically needed from term-sheet stage, since parties need to contractualise notification obligations and closing conditions. At that point, the data required for substantive analysis is rarely assembled. In a world where call-in risk turns on competitive dynamics, that gap has real consequences.

Most advisory teams will recognise what follows. Clients are rarely willing to commission external economic analysis at an early stage. The alternative is absorbing significant internal time to assemble fragmented market data, or delivering a caveated view that slows execution and dilutes the advice. Fee realisation, speed, and client confidence are all at stake.

The practical response is to bring forward elements of substantive analysis rather than treating jurisdictional and competition assessment as cleanly separable. In sectors with active regulatory attention, early-stage competition assessments covering concentration indicators, market structure, and threshold proximity are increasingly part of notifiability advice, not a later add-on.

Practices that build this capability are better placed to navigate discretionary regimes. They identify genuine risk earlier, avoid unnecessary escalation, and give clearer advice under time pressure. Jurisdictional certainty has diminished. The ability to combine speed with analytical depth has moved from differentiator to baseline expectation.