Ukrainian Law Expert Witness: What Surprises Foreign Counsel — and How to Avoid Them

When a tribunal issues a procedural order requiring Ukrainian law expert evidence, most foreign counsel do the obvious thing: search for a qualified Ukrainian lawyer who speaks English and has international arbitration experience.

The search produces names. The problem starts when the report arrives.

Ukrainian legal culture, academic tradition, and court practice differ from what international tribunals expect in ways that are not obvious from a CV. This article is not about how expert evidence works — you know that. It is about what is specific to Ukraine, where the surprises are, and what to check before you send the instruction letter.

For most jurisdictions, “qualified expert” means relevant practice experience and a credible professional background. For Ukrainian law in international proceedings, the qualification question has a specific dimension that matters particularly in civil law forums and investment arbitration: the distinction between a Doctor of Laws (Doktor yurydychnykh nauk) and a PhD in Law (Kandydat yurydychnykh nauk).

In Ukrainian academic tradition, these are two distinct degrees. The Doctor of Laws is a higher degree requiring an original doctrinal contribution — roughly equivalent in academic weight to a German Habilitation. The PhD is the first research degree.

This matters in practice because civil law courts in Switzerland, Austria, and the Netherlands, as well as investment arbitration tribunals evaluating the credibility of competing experts, place significant weight on academic standing. If opposing experts have stronger academic credentials, qualifications become a contested issue — and the gap between a Doctor of Laws with an active publication record and a PhD holder who stopped publishing after their dissertation becomes visible.

The critical point here is that the degree alone tells you almost nothing. The Ukrainian academic market produces large numbers of both Doctors of Laws and PhDs who defend their dissertations, publish the required articles beforehand, and then return entirely to practice. Their post-doctoral publication record is sparse or nonexistent. This is the norm, not the exception.

What actually matters for international proceedings is whether the expert has continued to engage substantively with Ukrainian law in writing after their doctoral work — whether through peer-reviewed academic publications, contributions to international legal encyclopedias such as Kluwer Law International, or sustained analytical writing on Ukrainian law questions that arise in cross-border practice.

What does “peer-reviewed” mean in this context?

For international tribunals, “peer-reviewed publications” means journals indexed in Scopus or Web of Science, or recognized international legal publications. Practical articles published on law firm websites or in Ukrainian business media demonstrate expertise but do not carry the same weight when expert qualifications are formally contested.

The single most consequential Ukrainian law provision for foreign counsel in commercial disputes is one that rarely receives attention in international contracts: Article 551 of the Civil Code of Ukraine.

Article 551 gives Ukrainian courts discretionary power to reduce contractual penalties they consider disproportionate. This is not a theoretical risk: courts exercise the discretion routinely, and in contested cases the reductions can be several-fold. A single percentage figure should not be quoted as a constant — the range turns on the circumstances, the wording of the contract and the relationship between the penalty and the actual loss, so it has to be checked against decisions on comparable facts before it goes into an opinion.

The implications are significant in two directions.

For transaction counsel: if your client’s contract with a Ukrainian party contains a penalty clause — 0.3% per day, liquidated damages, agreed compensation — and that dispute is resolved before a Ukrainian court or in arbitration applying Ukrainian law, the enforceability analysis is not complete without addressing Article 551. For a full overview of how we structure independent legal opinions on Ukrainian law for transactions and arbitration, see our dedicated practice page. The clause may be formally valid and still be reduced to a fraction of its stated value.

For litigation and arbitration counsel: the expert report needs to address not only whether the penalty clause is valid, but what range of reduction a Ukrainian court is likely to apply and why. An expert who simply confirms that the clause is “valid and enforceable” without addressing the Article 551 discretion has not answered the question that matters.

One important clarification: Article 551 applies when Ukrainian courts are deciding the dispute on the merits — either because Ukrainian law governs, or because the dispute is litigated in Ukraine from the outset. When a foreign arbitral award or court judgment is brought to Ukraine for recognition and enforcement, Ukrainian courts do not review the merits and do not apply Article 551 at that stage. The risk arises earlier — at the contracting or dispute resolution stage, not at the enforcement stage.

It is also worth noting that Ukraine is currently developing a new Civil Code. Article 551 in its current form may not survive the reform unchanged. An expert opining in current proceedings should address the provision as it stands while noting this legislative context.

Ukrainian law has undergone significant reform since 2016 — the judiciary was restructured, the Supreme Court was reconstituted, and a substantial body of new case law has developed on commercial law questions. In several areas that arise frequently in international proceedings, the Supreme Court’s current position differs materially from a straightforward reading of the statutory text.

Set-off of cross-claims

A concrete example that arises regularly in international trade and cross-border transactions: the general rule under Ukrainian civil law permits set-off of homogeneous counterclaims. This is the statutory position. But during martial law, specific restrictions apply to set-off in foreign trade contracts — and the Supreme Court has issued decisions pointing in both directions on the scope of these restrictions. An expert who cites the general rule without engaging with the martial law overlay and the current state of Supreme Court practice is giving you an incomplete answer.

Limitation periods

The general three-year limitation period is well known. The Supreme Court’s jurisprudence on when the period begins to run — particularly in cases involving continuing obligations, installment payments, and guarantees — has developed in ways that are not immediately apparent from the statute. This is an area where the judicial practice is the material source, not the Civil Code provision.

Corporate validity

The Supreme Court has issued significant decisions on the consequences of procedural defects in shareholder meetings and on questions of director authority. An expert opining on the validity of a corporate resolution needs to engage with this jurisprudence, not just with the Companies Act provisions.

Ukraine ratified the Cape Town Convention and the Aircraft Protocol. For aviation counsel instructing on a Ukrainian law opinion for a lease or financing transaction, this should mean standard Cape Town analysis. In practice, there is a gap between ratification and implementation that is material for lessors and lenders.

IDERA effectiveness

The Irrevocable Deregistration and Export Request Authorization is the mechanism that gives lessors practical repossession rights under Cape Town. In Ukraine, the administrative practice around IDERA processing — who processes it, in what timeframe, and what documentation is required — has not always aligned with the Convention’s intent. Expert analysis needs to address not just the legislative framework but the administrative reality.

Interaction with Ukrainian insolvency law

When a Ukrainian airline enters insolvency proceedings, the interaction between Cape Town creditor protections and Ukrainian insolvency moratorium provisions creates a zone of uncertainty. The statutory text suggests Cape Town protections prevail. The judicial practice is less uniform. An expert who addresses only the statutory text without engaging with how Ukrainian insolvency courts have actually treated aviation creditors is not giving you the full picture.

Security interest priority

The priority rules for registered international interests under Cape Town interact with Ukrainian domestic security law in ways that require careful analysis when multiple creditors are involved.

The most common failure mode for Ukrainian expert reports in international proceedings is not factual error — it is a structural mismatch between Ukrainian academic legal writing style and what international tribunals expect.

Ukrainian legal scholarship is heavily doctrinal. It explains legislative history, analyses competing academic positions, and situates the specific question within the broader framework of Ukrainian civil law doctrine. This is intellectually rigorous. It is also exactly what makes a report vulnerable when the opposing expert takes a different view, and the tribunal needs to choose between them.

The standard that international tribunals apply is: can you show me what Ukrainian courts do with this provision, not just what the provision says? An expert who has analyzed the doctrine extensively but cannot point to specific judicial decisions supporting the conclusions is offering an academic opinion rather than evidence of Ukrainian law in action.

Cross-examination of a Ukrainian law expert is not routine — it occurs when the opposing party genuinely contests the conclusions, and the tribunal decides that oral evidence is needed. When it does happen, the questions focus on exactly this: which specific decisions support your analysis, how you account for decisions that point the other way, and what your methodology is for resolving inconsistent practice.

Ukrainian law experts who appear in international proceedings constitute a relatively small professional community. The aviation finance bar, the investment arbitration community, and the commercial disputes community in Ukraine overlap significantly.

This creates a practical complication: conflict checks matter more, and the conflicts are less obvious.

A Ukrainian lawyer who provided a transaction opinion for one party several years earlier may not immediately recognize the conflict when instructed as an expert in subsequent litigation arising from the same transaction. A lawyer who has written publicly about a specific Ukrainian law question — in an article, a prior expert report, or a conference paper — has a prior position that opposing counsel will find and use. Our expert witness practice covers proceedings before English courts, US courts, and all major arbitration institutions.

These are not due diligence questions for a junior associate. These are questions for the direct conversation with the expert.

First: “In your most recent expert engagement, what was the most substantively difficult Ukrainian law question you addressed, and how did you resolve the uncertainty in the sources?” A credible expert will have a specific, technically grounded answer. Vagueness here is a signal.

Second: “Where Ukrainian judicial practice on this question is inconsistent or developing, how do you present that in the report?” The right answer involves acknowledging the inconsistency, explaining the range of outcomes, and giving a reasoned conclusion with appropriate qualification. An expert who says “Ukrainian law clearly provides X” on a question where Supreme Court practice is genuinely split is either unaware of the complexity or shading toward advocacy.

Third: “Have you previously expressed a view — in writing, in a prior report, or in a publication — on the specific Ukrainian law question we are asking you to address?” If yes, that prior view needs to be disclosed and assessed before instruction, not discovered by opposing counsel.

Written by Anna Tsirat, Doctor of Laws, partner at Jurvneshservice. She has acted as a Ukrainian law expert in proceedings before the Permanent Court of Arbitration (The Hague) and the High Court of Justice (London), and before courts in the United States, Switzerland and the Netherlands, including in AMTO v. Ukraine (SCC).

Published 13 August 2026; this guide replaced an earlier page, “Ukrainian Legal Expert Opinion for International Courts and Arbitration”, which described the same service more briefly. The rule on reducing contractual penalties is stated under article 551(3) of the Civil Code of Ukraine as in force. Supreme Court practice on the questions discussed here is still developing and the Civil Code is under revision — verify the current wording and the current case law before an opinion is prepared.