Post‑m&a Disputes in Poland 2026: Earn‑outs, Price Adjustments & W&I Claims, Arbitration vs Courts Explained

Introduction, The 2026 landscape for post m&a disputes poland

Post m&a disputes poland has become one of the most commercially significant areas of contentious practice as deal volumes recover and sellers, buyers and insurers contest the true value of completed transactions. The May 2026 Warsaw conference on dispute resolution in M&A transactions reflects a broader reality: earn‑out mechanisms, completion accounts and W&I policies now generate a steady flow of high‑value claims that turn on both accounting detail and forum strategy. For general counsel and private equity sponsors, the question is rarely whether a dispute can be brought, but where it should be brought, how quickly interim protection can be secured, and whether any award or judgment will be enforceable against the counterparty’s assets.

This guide sets out the practical mechanics of post‑closing disputes under Polish law, compares arbitration with the ordinary courts, and offers checklists for claimants and respondents preparing for 2026 transactions.

Overview, Types of post‑M&A disputes in Poland

Post‑closing disputes in Poland cluster around a handful of recurring transaction structures. Each has its own evidentiary profile, contractual triggers and commercial stakes, and each is shaped by the drafting choices made in the share purchase agreement (umowa sprzedaży udziałów/akcji, the SPA). Understanding the categories is the first step in choosing a forum and building a recovery strategy.

• Earn‑out disputes. Where part of the consideration is contingent on post‑closing performance, typically EBITDA, revenue or customer‑retention targets, buyers and sellers frequently disagree on how the relevant metric was calculated, whether the business was operated in good faith, and whether accounting policies were applied consistently. These are among the most contested post‑M&A disputes in Poland because they combine contractual interpretation with forensic accounting.
• Completion accounts disputes. Under a completion‑accounts mechanism, the final price is fixed by reference to net debt and working capital measured at closing. Disagreements arise over the classification of items, provisions, cut‑off dates and the consistency of accounting policies with the SPA’s agreed principles.
• Purchase price adjustment disputes. Related to completion accounts, these concern the arithmetic and contractual mechanics of adjusting the headline price up or down, including the treatment of leakage in locked‑box deals and the interaction of caps, collars and interest.
• Warranty and indemnity (W&I) claims. Breaches of warranties in the SPA, or triggering of specific indemnities, may be pursued against the seller or channelled through a W&I insurance policy. Coverage disputes, notification defences and the interplay between contractual limitation and policy terms are common.

A single transaction can generate several of these claims at once, for example, a buyer disputing an earn‑out figure while also notifying a warranty breach and pursuing the W&I insurer. The commercial stakes are typically substantial, and the forum decision made at the drafting stage will govern how each of these post‑closing disputes is resolved.

Choosing the forum, arbitration vs Polish courts for post m&a disputes poland

The single most consequential decision in any post‑M&A dispute is whether the claim proceeds before an arbitral tribunal or the ordinary Polish courts. That choice is usually locked in at signing by the dispute‑resolution clause, so it deserves careful attention long before any conflict arises. The relevant considerations are seat, language, confidentiality, availability of interim relief, finality, appeal or set‑aside rights, cost and predictability.

M&a arbitration poland is popular in cross‑border and sponsor‑backed transactions because it offers a neutral seat, confidentiality, party‑appointed arbitrators with sector expertise, and, critically, an award that is enforceable in the many states party to the New York Convention. The Polish courts, by contrast, offer lower up‑front cost, a public and precedent‑generating process, and direct access to the state’s coercive enforcement machinery without a separate recognition step.

When arbitration is preferable

• Cross‑border enforcement. Where the seller’s assets sit outside Poland, an arbitral award enforceable under the New York Convention is often more portable than a Polish court judgment, particularly outside the EU.
• Confidentiality. Sensitive commercial terms, valuations and reputational issues are kept out of the public record.
• Specialist decision‑makers. Parties can appoint arbitrators with accounting, valuation or sector experience, which matters in technical earn‑out and completion‑accounts disputes.
• Finality. Arbitral awards are generally not subject to appeal on the merits, only to narrow set‑aside grounds, which can shorten the overall timeline.

When courts are preferable

• Lower value or purely domestic disputes. Where both parties and all assets are Polish, the ordinary courts avoid the cost of an arbitral institution.
• Need for precedent or public vindication. Some claimants prefer a published judgment, particularly where a point of principle is at stake.
• Multi‑party or third‑party claims. Where non‑signatories must be joined, court proceedings can be simpler than assembling consent to arbitration.
• Certain interim measures. Polish courts retain competence over coercive provisional measures, discussed below.

The comparison table later in this guide sets out these vectors side by side. The general drafting lesson is that the forum clause should be aligned with the likely dispute profile and the location of enforcement targets, and should expressly capture accounting and expert‑determination disputes so that no jurisdictional gap arises.

Enforcement & interim relief, practical steps in Poland

Winning on the merits is only half the battle. In post‑M&A disputes the practical value of any claim depends on the claimant’s ability to secure assets early and to convert an award or judgment into recovery. Poland offers a workable framework for both provisional measures and enforcement, but the procedural routes differ between arbitration and court proceedings.

Emergency arbitration and arbitral emergency measures

Many leading arbitral rules permit a tribunal, once constituted, to order interim measures such as security, preservation of evidence and orders restraining the disposal of assets. Several institutions also provide emergency‑arbitrator procedures that allow an applicant to obtain urgent relief before the full tribunal is appointed. These measures bind the parties, but they are not directly executed by the state’s bailiffs; where coercive enforcement against a recalcitrant party or a third party is required, the applicant will usually still need the assistance of the Polish courts.

Polish courts’ role in provisional measures

The Polish Code of Civil Procedure (Kodeks postępowania cywilnego) governs the granting of security for claims (zabezpieczenie roszczeń), including freezing‑style measures over bank accounts, receivables and other assets. A claimant must generally show that the claim is credible (uprawdopodobnienie roszczenia) and a legal interest in obtaining security, typically the risk that enforcement will otherwise be frustrated. Applications can be made before or during proceedings and, in urgent cases, may be decided quickly and without notice to the respondent. Critically, Polish courts can grant interim measures in support of both domestic litigation and arbitration, including arbitration seated abroad, which makes them an essential tool even where the merits are arbitrated.

On enforcement of final decisions, the position depends on the instrument:

• Foreign arbitral awards are recognised and enforced in Poland under the New York Convention (1958), to which Poland is a party. Recognition may be refused only on the narrow grounds listed in the Convention, principally invalidity of the arbitration agreement, denial of due process, excess of mandate, or conflict with Polish public policy (klauzula porządku publicznego).
• Domestic arbitral awards are enforced through a court declaration of enforceability under the Code of Civil Procedure, after which they carry the same force as a court judgment.
• Court judgments, once final and endowed with an enforcement clause (klauzula wykonalności), where required, are executed by a court enforcement officer (komornik sądowy).

Before launching either provisional measures or enforcement, claimants should identify the counterparty’s assets. A search of the National Court Register (Krajowy Rejestr Sądowy, KRS) via the official register portal reveals corporate structure, management, and filed financial statements, and helps map viable enforcement targets.

Earn‑outs & completion accounts, dispute mechanics and evidence plan

Earn‑out disputes poland and completion accounts dispute poland claims are won and lost on documents and expert analysis. Because these disputes are fundamentally about numbers and the contractual rules that generate them, the party that preserves and marshals the accounting record most effectively usually prevails. The mechanics fall into two overlapping tasks: interpreting the SPA’s accounting and calculation provisions, and reconstructing what actually happened in the target business after closing.

Forensic accounting & document preservation

The moment a dispute is anticipated, both sides should preserve the relevant records. A typical evidence checklist for an earn‑out or completion‑accounts dispute includes:

1. The signed SPA with all schedules, particularly the agreed accounting policies and the earn‑out or completion‑accounts mechanism.
2. Draft and final completion accounts, working‑capital and net‑debt schedules, and the accompanying reconciliations.
3. The target’s management accounts, general ledger, trial balances and audit files for the relevant periods.
4. Board minutes, budgets and internal correspondence bearing on how the business was run during the earn‑out period.
5. Contemporaneous emails and instructions to the preparing accountants, which often reveal the reasoning behind contested entries.

Forensic accountants are then instructed either as expert witnesses in arbitration or litigation, or as an independent expert deciding a defined question. The distinction matters: an expert witness gives an opinion that the tribunal weighs, whereas an expert determination (often an independent accounting firm named in the SPA) produces a binding conclusion on the disputed figures, usually with very limited grounds for challenge.

Typical contractual remedies

The remedy in an earn‑out or completion‑accounts dispute is generally monetary, payment of the disputed portion of the consideration, or adjustment of the price, together with contractual interest. Well‑drafted SPAs specify the interest rate, the payment mechanics following a determination, and any set‑off against escrow or retention amounts. Where the buyer is alleged to have manipulated the earn‑out metric, for example by diverting revenue or changing accounting policies, the seller may also claim damages for breach of the good‑faith operating covenants that sophisticated earn‑out clauses now routinely contain. Preserving evidence of how the business was operated is therefore as important as the accounting record itself.

Purchase price adjustments & SPA drafting checklist

Most purchase price adjustment dispute poland claims can be prevented, or at least narrowed, by disciplined drafting. The following checklist captures the clauses that most often become the battleground and the drafting choices that reduce ambiguity:

• Calculation mechanics. Set out the precise formula for net debt, working capital and any adjustment, with a worked example annexed to the SPA so the parties share a common arithmetic starting point.
• Accounting policies hierarchy. State the order of priority, specific SPA policies first, then the target’s consistent past practice, then the applicable accounting standards, to resolve the classic “consistency versus standards” argument.
• Timing. Fix clear deadlines for delivery of draft accounts, for objections, and for the escalation of unresolved items, with the consequences of missing each deadline spelled out.
• Dispute escalation. Provide a staged process, good‑faith discussion, then referral of remaining items to an independent expert, then, if necessary, arbitration or the courts, and define the expert’s remit tightly.
• Interest and caps. Specify the interest that accrues on adjustment amounts and any caps, collars or de minimis thresholds.

A short, neutral sample formulation for the escalation mechanism might read: “Any item of the completion accounts remaining in dispute after 20 business days of good‑faith discussion shall be referred to an independent expert, acting as expert and not as arbitrator, whose decision on that item shall be final and binding save in the case of manifest error or fraud.” Precise language of this kind confines the dispute and shortens any subsequent proceedings.

W&I insurance claims in Poland, notification, coverage disputes & recovery

W&i insurance claims poland have grown in step with the wider adoption of warranty and indemnity insurance on Polish deals. A W&I policy shifts the risk of warranty breaches from the seller to an insurer, but it introduces its own procedural discipline and a distinct set of potential defences. Handling a claim correctly from the first notification is essential to recovery.

The claim process typically runs as follows: the insured discovers a potential breach or loss, notifies the insurer within the period and in the form required by the policy, provides supporting information, and cooperates with the insurer’s investigation. Failure to observe notice and cooperation requirements is one of the most common reasons a claim is contested. Insurers may also invoke coverage defences based on:

• Knowledge and disclosure carve‑outs, matters the buyer knew about, or that were fairly disclosed, are typically excluded.
• Materiality and de minimis thresholds, losses below the agreed threshold or retention are not recoverable.
• Scope exclusions, specific risks identified in diligence are commonly excluded and left to be addressed by specific indemnities.
• Quantum and mitigation, disputes over the measure of loss and the insured’s duty to mitigate.

Insurers carrying on insurance business in the Polish market fall within the supervisory remit of the Polish Financial Supervision Authority (Komisja Nadzoru Finansowego, KNF), which is the relevant regulator for the insurance sector in Poland. Note that many W&I policies placed on Polish deals are underwritten by insurers established elsewhere in the EEA operating under freedom of services. Where a coverage dispute cannot be resolved, it is pursued according to the dispute‑resolution clause in the policy, which may point to arbitration or the courts independently of the SPA’s forum.

Interaction with M&A indemnities and limitation periods

W&I cover does not exist in isolation. It sits alongside the seller’s contractual warranties and indemnities, and the two must be read together. Specific indemnities negotiated for known risks may respond where the policy excludes them; conversely, the policy may respond where the seller’s liability is capped at a nominal amount. Limitation is critical: contractual claim periods for warranties and the notification periods under the policy run on different clocks, and a claimant who observes one but misses the other loses cover. Statutory limitation of contractual claims is governed by the Polish Civil Code (Kodeks cywilny), and any assessment of a live claim should begin by confirming both the statutory limitation position and the contractual and policy deadlines.

Procedure, timelines & costs, arbitration vs litigation in Poland

Realistic expectations on timing and cost are central to any settlement strategy. Both arbitration and litigation follow a broadly similar arc, pre‑action correspondence, commencement, exchange of submissions and evidence, hearing, and decision, but the pace and cost profile differ.

The practical sequence for a post‑closing dispute usually runs:

1. Pre‑action. Preserve evidence, instruct forensic accountants, notify insurers where a W&I policy is engaged, and issue a letter setting out the claim.
2. Interim protection. Where dissipation of assets is a risk, apply for security or provisional measures without delay, before or at the point of commencement.
3. Commencement. File the request for arbitration or the statement of claim, triggering the institutional or court timetable.
4. Evidence and hearing. Exchange pleadings, documents and expert reports, then proceed to a hearing.
5. Award or judgment and enforcement. Obtain the decision, then move to recognition and enforcement as required.

On cost, court litigation in commercial matters generally carries a statutory filing fee calculated as a percentage of the claim value, subject to a statutory cap set out in the Act on Court Costs in Civil Matters (ustawa o kosztach sądowych w sprawach cywilnych), plus counsel and expert fees. Arbitration adds the arbitrators’ fees and the institution’s administrative charges, which are typically higher up front, but the process can be faster and more predictable, and finality removes the cost of appeals. In technical earn‑out and completion‑accounts disputes, forensic accounting fees are frequently the largest single line item on either route. Cross‑border enforcement of an arbitral award adds a further recognition step.

These trade‑offs feed directly into the forum decision made at drafting.

Decision tree & practical next steps for claimants and respondents

When a post‑closing dispute crystallises, the first hours and days often determine the outcome. The following sequence applies to most post m&a disputes poland scenarios:

1. Preserve evidence immediately. Suspend routine deletion, secure accounting records, and ring‑fence the relevant management correspondence.
2. Check the forum clause. Confirm whether the SPA or policy points to arbitration or the courts, and whether accounting disputes are carved out to an independent expert.
3. Assess urgency. If there is any risk of asset dissipation, prepare an application for security or provisional measures at once.
4. Notify insurers. Where a W&I policy is in play, give notice strictly in accordance with its terms and begin the cooperation process.
5. Map enforcement targets. Run a KRS search and identify assets against which any award or judgment could be enforced.
6. Choose the recovery route. Weigh expert determination for arithmetic disputes against full arbitration or litigation for contested factual and legal questions.

Respondents should mirror these steps, preserving their own records, testing the validity of the claim against the SPA’s limitation and notice provisions, and scrutinising any interim application on the merits and on proportionality. Because the strategic and evidential stakes are high, parties on either side of a Polish post‑closing dispute should take specialist advice early; the Dispute Resolution Lawyer, Poland practice page is a useful starting point for finding qualified counsel.

Comparison table, arbitration vs courts for post m&a disputes poland

Image alt: Arbitration vs Court proceedings for post m&a disputes in Poland, 2026 infographic.

Case studies & Polish precedents, practical takeaways

Polish jurisprudence on the enforcement of arbitral awards and on provisional measures underpins the strategic choices set out above. The Supreme Court of Poland (Sąd Najwyższy) is an authoritative source for rulings on the recognition and enforcement of awards, the scope of the public‑policy exception, and the application of the Code of Civil Procedure to interim measures. Its published judgments reflect the consistent principle that the public‑policy ground for refusing recognition is construed narrowly and does not permit a review of the merits of the award, a point of considerable comfort to parties who arbitrate cross‑border M&A claims and expect to enforce in Poland.

Two practical takeaways emerge from the Polish enforcement framework. First, an arbitral award that is procedurally sound and within the tribunal’s mandate will, as a rule, be recognised and enforced in Poland, and challenges based on a re‑argument of the facts will generally fail. Second, the courts’ willingness to grant security for claims in support of arbitration, including arbitration seated abroad, means that a claimant need not sacrifice the protective machinery of the state simply because it has chosen a private forum. Parties preparing a claim should confirm the current position by consulting the Supreme Court’s published judgments for the latest citations before relying on any specific ruling.

Conclusion, a recommended approach to post m&a disputes poland in 2026

The right strategy for post m&a disputes poland begins long before any disagreement, in the drafting of the SPA and any W&I policy. Align the forum clause with the likely dispute profile and the location of enforcement targets; carve out accounting disputes to a tightly defined independent expert; specify calculation mechanics, timing and interest with precision; and coordinate the contractual limitation periods with any policy notice deadlines. When a dispute does arise, preserve evidence at once, assess the need for provisional measures, notify insurers strictly per the policy, and map enforcement targets through the KRS before committing to a recovery route.

Arbitration offers confidentiality, specialist decision‑makers and portable enforcement under the New York Convention; the Polish courts offer lower up‑front cost, direct coercive enforcement and a public record. Choosing between them, and executing the surrounding procedure well, is what converts a paper claim into real recovery. For tailored guidance on any of these questions, contact the Global Law Experts Poland dispute resolution team.

Sources

1. Internetowy System Aktów Prawnych (ISAP), Sejm of the Republic of Poland
2. Ministry of Justice, Republic of Poland
3. National Court Register (KRS), Ministry of Justice
4. Supreme Court of Poland (Sąd Najwyższy)
5. Polish Financial Supervision Authority (KNF)
6. Naczelna Rada Adwokacka (Polish Bar Council)
7. UNCITRAL, New York Convention (1958)