Voluntary Merger Notification vs No Notification in the Czech Republic (2026): When to File, Call‑in Risks and How to Decide

Deal teams closing transactions with a Czech nexus now face a sharper version of an old question: voluntary merger notification vs no notification in the Czech Republic, which path protects value and which invites regulatory disruption? The 2025–2026 reforms to the Czech Competition Act introduced a targeted call‑in model that lets the Office for the Protection of Competition (OPC) reach transactions that previously fell outside its jurisdiction, fundamentally changing the risk calculus for acquirers, sellers and joint‑venture partners. This guide sets out the two options side by side, quantifies the cost‑time‑risk tradeoffs dimension by dimension, and delivers a concrete decision framework so you can act, or engage counsel, within 48 hours.

Option A: Voluntary Notification, What It Is, When It Applies and Who It Suits

Legal basis and formality

Under the Czech Competition Act (Act No. 143/2001 Coll., on the Protection of Competition), a merger that meets the statutory turnover thresholds triggers a mandatory notification obligation. The notification must follow the prescribed form set out in Decree No. 252/2009 implementing the Act. The OPC also accepts voluntary notifications for transactions that fall below the mandatory thresholds but may raise competitive concerns, a route that has gained practical importance since the 2025–2026 reforms. Pre‑notification consultation with the OPC is available on a voluntary basis and, while not a formal condition for filing, is strongly recommended by the regulator.

When to file voluntarily

Voluntary filing is most relevant in four situations:

• Market overlap. The parties compete or operate along the same supply chain in Czech markets, even if turnover thresholds are not met.
• Near‑threshold turnover. Combined or individual Czech turnover is close to the mandatory filing thresholds, creating ambiguity.
• Joint‑venture formation. The reformed rules change how JVs are assessed, filing voluntarily eliminates post‑closing uncertainty.
• Remedy appetite. The buyer or seller prefers to negotiate remedies before closing rather than face a retrospective call‑in.

Advantages of voluntary filing

Voluntary notification delivers three concrete benefits. First, it provides legal certainty before closing: once the OPC clears the transaction, there is no residual call‑in exposure. Second, it gives the parties control over timing, the notification can be filed after signing (or even before, on the basis of a sufficiently concrete intention to merge), allowing remedy discussions to run in parallel with deal execution. Third, voluntary filers can shape the narrative: they present the competitive assessment proactively rather than responding to an OPC investigation that is, by design, adversarial. For cross‑border deals requiring multi‑jurisdictional clearance, voluntary Czech filing also simplifies the coordination timetable.

Option B: Proceeding Without Notification

Legal baseline, mandatory vs discretionary filing

Filing is mandatory only where the statutory turnover thresholds are met. If a transaction falls below those thresholds, there is no legal obligation to notify, and the parties are free to close without OPC approval. However, the 2025–2026 reforms introduced a targeted call‑in power that allows the OPC to request a notification even for below‑threshold transactions that may significantly distort competition, provided certain conditions are satisfied and the call‑in occurs within the prescribed window after completion. The details of the thresholds and call‑in criteria are analysed in the dimension‑by‑dimension section below.

When parties commonly proceed without filing

Non‑notification is the standard path when the transaction has minimal Czech market impact: turnover is well below thresholds, the parties do not compete in the Czech Republic, and there are no vertical or conglomerate links that could trigger the OPC’s call‑in criteria. It is also preferred when closing speed is paramount and any pre‑closing regulatory process would jeopardise deal economics or exclusivity deadlines.

Advantages of proceeding without notification

The case for non‑notification rests on speed, cost and confidentiality. There is no notification fee to pay, no formal document assembly or Decree‑compliant filing to prepare, and no public disclosure of the transaction in OPC records. The deal can close on its own commercial timetable. For transactions with no realistic prospect of call‑in, because the parties have no Czech competitive overlap and combined Czech turnover is negligible, proceeding without notification is both efficient and rational. The residual risk is that the OPC exercises its call‑in power within the statutory window, at which point the parties must respond retroactively, potentially while the merged business is already operating.

Side‑by‑Side Comparison: Voluntary Notification vs No Notification in the Czech Republic

Key takeaways from the comparison:

• Voluntary notification eliminates call‑in risk entirely and puts remedy design in the parties’ hands.
• Proceeding without notification is faster and cheaper, but only if call‑in probability is genuinely low.
• The 2026 reforms make call‑in probability harder to dismiss: competition counsel should assess it for every deal with Czech overlap.

Dimension‑by‑Dimension Analysis: Voluntary Filing vs No Notification

Eligibility and merger notification thresholds in the Czech Republic

Under the Czech Competition Act, a merger must be notified when the parties’ turnover exceeds specified monetary thresholds. The existing regime requires notification where the combined net turnover of all parties in the Czech Republic exceeds CZK 1. 5 billion and each of at least two parties achieves Czech turnover exceeding CZK 250 million. An alternative limb captures transactions where one party’s worldwide turnover exceeds CZK 1. 5 billion and another party’s Czech turnover exceeds CZK 250 million. The 2025–2026 reform package increased these monetary thresholds, the first adjustment in over 20 years, and modified how JV transactions trigger a mandatory filing obligation, requiring that the JV itself or both parents generate local Czech turnover.

Transactions that fall below these thresholds are not required to notify but are exposed to the new call‑in mechanism.

Cost and fees

Note: counsel fee estimates are indicative benchmarks based on practitioner guidance and should be confirmed with Czech competition counsel for the specific transaction.

Timing and procedural windows

The OPC encourages, but does not require, pre‑notification contacts before formal filing. Once a complete notification is submitted, Phase I review runs for 30 days. If the OPC identifies serious competition concerns, it may open a Phase II investigation lasting up to five months. The notifying party may file as soon as binding transaction documents are signed, or even earlier based on a demonstrated serious intention. For parties that choose not to notify, the critical timeline is the six‑month call‑in window: the OPC may call in a below‑threshold transaction within six months of its completion where it suspects the merger may significantly distort competition.

Filing voluntarily before or immediately after signing effectively resets this clock to zero, because OPC clearance extinguishes the call‑in power.

Liability, fines and gun‑jumping risk

The risks of not notifying a transaction that meets the mandatory thresholds are severe: the OPC can impose administrative fines of up to 10% of the undertaking’s net turnover and may order the transaction to be unwound. Gun‑jumping, implementing a notifiable concentration before clearance, carries the same penalty framework. For below‑threshold transactions that are called in, the parties face comparable enforcement exposure from the moment the OPC issues the call‑in request. Voluntary notification pre‑empts all of these risks. Industry observers expect the OPC to use its new call‑in authority selectively but firmly, particularly in concentrated Czech markets such as retail, media, telecoms and healthcare.

Enforceability and remedies

When the OPC identifies competition concerns, it may impose structural remedies (divestiture of business units or assets) or behavioural remedies (commitments on pricing, access, or non‑discrimination). Voluntary filers negotiate these remedies during the review, typically in Phase II, and can tailor commitments to minimise operational disruption. Parties that are called in post‑closing face the same remedy toolkit, but with less negotiating leverage: the merged entity is already operating, and the OPC’s bargaining position is stronger because it can threaten to unwind the transaction entirely. The likely practical effect of the 2026 reforms is that post‑closing remedies will be more disruptive and more costly than pre‑closing commitments.

What Changes in Czech Merger Control in 2026

The 2025–2026 reform of Czech competition law represents the most significant overhaul of the merger control regime in over two decades. Three changes are directly relevant to the voluntary merger notification vs no notification decision:

• Targeted call‑in model. The OPC can now call in below‑threshold transactions within six months of completion where it suspects significant competitive distortion, the combined net turnover of the parties in the Czech Republic meets a lower call‑in threshold, and the transaction affects a Czech market. This power did not previously exist.
• Increased monetary thresholds. The mandatory notification thresholds have been raised for the first time since the Act entered into force, narrowing the scope of mandatory filing but expanding the universe of transactions that sit below thresholds yet may still be called in.
• JV treatment. A JV now triggers mandatory notification only where the JV itself or both of its parent undertakings generate local Czech turnover, reducing the number of JVs caught by mandatory filing but leaving them exposed to call‑in if they affect Czech competition.

The net effect: more transactions fall below the mandatory thresholds, but the OPC has a new tool to reach the ones that matter. Voluntary filing is the only reliable way to neutralise that residual risk before closing.

Decision Framework: Should I Notify or Proceed Without Filing?

Choose voluntary notification when:

• The parties overlap in one or more Czech product or geographic markets.
• Combined Czech turnover is near or above the mandatory thresholds (even if marginally below).
• The transaction involves a JV that will be active in Czech markets.
• The buyer or seller cannot tolerate post‑closing regulatory disruption or divestiture risk.
• The deal requires multi‑jurisdictional merger clearance and a Czech filing would simplify coordination.
• Market share in any relevant Czech market exceeds 25% post‑transaction.

Choose to proceed without notification when:

• Neither party generates material turnover or has competitive presence in the Czech Republic.
• Combined Czech turnover is well below the call‑in threshold and there are no horizontal, vertical or conglomerate overlaps.
• Closing speed and transaction confidentiality outweigh the residual call‑in risk.
• Competition counsel has confirmed in writing that call‑in probability is negligible.

Quick five‑question screening checklist:

If you answer “yes” to two or more questions, voluntary notification is the recommended path. If you answer “yes” to even one question and cannot confidently rule out call‑in risk, engage Czech competition counsel before signing.

When to Engage a Competition Lawyer for This Decision

The filing‑or‑not decision should not be made by deal teams alone. Engage specialist Czech competition lawyers at one of these trigger points:

• Pre‑LOI / term sheet stage: If preliminary diligence reveals Czech market overlaps or near‑threshold turnover.
• Pre‑signing: To obtain a written filing risk assessment and, if needed, to initiate pre‑notification contacts with the OPC.
• Pre‑closing: If the filing decision has been deferred and new information (market data, competitor complaints) changes the risk profile.
• Immediately upon call‑in: If the OPC exercises its call‑in power post‑closing, retain counsel within 48 hours, response timelines are compressed.

For the first meeting, prepare the following:

• Audited turnover schedules for all parties (Czech and worldwide, last accounting period)
• Product and service overlap maps for Czech markets
• Market share estimates for affected Czech markets
• Redacted transaction documents (SPA, SHA or JV agreement)
• Any prior OPC correspondence or competition authority decisions involving the parties

For a straightforward filing risk assessment, early indications suggest that most Czech competition specialists offer fixed‑fee or capped‑fee engagements. Complex filings involving remedies negotiation typically move to hourly billing. Consult the Czech Republic competition practice area for guidance on selecting counsel.

Sources

1. Úřad pro ochranu hospodářské soutěže (UOHS), Official Website
2. Lex Mundi, Czech Republic Merger Notification Guide
3. Havel & Partners, A New Era of Merger Control: The Targeted Call‑In Model
4. Wolters Kluwer, Czech Competition Enforcement Facing Major Changes
5. Schoenherr, Czech Republic Merger Control Guide
6. Chambers Practice Guides, Merger Control 2025: Czech Republic
7. Rowan Legal, Call‑In Model in Czech Merger Control
8. International Competition Network, Czech Republic Merger Template
9. UOHS, Notice on Pre‑Notification Contacts in Mergers