Legal Q&A · Debt Recovery

The debtor says nothing is owed because it set off its own claim. Is that valid?

Law as at 10 September 2026

Answered by , Czech and Slovak attorney, admitted to the Slovak and Czech Bars (SAK 300422 · ČAK 19654).

Short answer

A unilateral set-off may extinguish a debt if the mutual claims are eligible for set-off and a definite declaration has been delivered to you. Maturity is generally required, but the Commercial Code provides exceptions in Sections 359 and 360. The mere fact that a counterclaim is disputed does not make it ineligible for set-off; its existence, amount and the other conditions must be examined. If the conditions are not met, the set-off does not extinguish the debt.

This is a common defence to invoice recovery: the debtor announces set-off of its own claim, typically damages, a price reduction or older invoices, then refuses further communication. Whether the set-off stands is assessed under fairly strict Civil Code (Act No. 40/1964 Coll.) and Commercial Code (Act No. 513/1991 Coll.) rules.

When unilateral set-off actually extinguishes debt

Where creditor and debtor have mutual claims for performance of the same kind, the claims are extinguished by set-off to the extent they overlap if either party makes a declaration of set-off to the other. Extinction takes effect when the claims became eligible for set-off against each other.

— Section 580 of the Civil Code (unofficial English translation)

Neither the other party’s consent nor a court decision is required. In case No. 2Obdo/34/2024, the Slovak Supreme Court reiterated that extinction by set-off does not depend on a judgment. An effective declaration operates retrospectively from the point the claims became mutually eligible, as explained in case No. 4Obdo/87/2021, so default interest also stops from then to the extent of the overlap. Between businesses, claims enforceable in court are eligible for set-off (Section 358 of the Commercial Code). Parties may agree to set off any mutual claims under Section 364, but this flexibility does not apply to a unilateral declaration.

The most common defect: set-off before maturity

An unmatured claim cannot be set off against a due claim, unless it is a claim against a debtor unable to meet its monetary obligations.

— Section 359 of the Commercial Code (unofficial English translation)

Both claims must generally be due; the law nevertheless provides, for example, the insolvency exception in Section 359 and permits set-off against a creditor’s unmatured claim under Section 360 of the Commercial Code. In case No. 5Obo/12/2019, the Slovak Supreme Court emphasised that damages become due only when asserted against the liable party through a demand, and set-off can be declared only afterwards. A debtor who never quantified damages or demanded payment but immediately announced set-off has therefore generally extinguished nothing.

What to check in a set-off notice

Work through four questions. Does the counterclaim exist, and on what basis? Merely asserting damages or a discount does not establish a claim. Were the maturity requirements met, or did a statutory exception under Section 359 or Section 360 apply? Does the declaration clearly identify which claim is set off against which, and for what amount? Was it delivered to you? A time-barred counterclaim cannot be unilaterally set off (Section 581(2) of the Civil Code). In commercial relations, limitation does not prevent set-off only where it arose after the claims became eligible (Section 358). See when a claim becomes time-barred.

How to respond

If a condition is missing, reject the set-off in writing with reasons, dispute the counterclaim’s basis and amount, and demand payment. Recovery then follows the ordinary unpaid-invoice route, including litigation, summarised in how to recover an unpaid invoice. If part of the counterclaim is justified, the dispute narrows to the balance.

How we can help

Our assignment and set-off service assesses notices and prepares reasoned responses, or structures your own effective declaration. We recover the remaining claim through debt recovery and handle set-off litigation through court representation.

Do not file away a disputed set-off. Every month of silence may later be interpreted against you.

This answer provides general information on the law as at 10 September 2026. It does not constitute legal services or replace an assessment of an individual case. The details of your situation may differ. Book a consultation to discuss them.

More legal questions

All questions and answers
  1. What is a payment order and how can I challenge it? A payment order is a summary court decision requiring the debtor, without a hearing, to pay the claim and costs within 15 days or file an objection within the same period. A timely objection supported by substantive reasons sets the order aside and the dispute continues; in separate procedural joinder, however, one defendant's objection does not set the order aside against the others. Without an objection, the order becomes final and enforceable. Separate electronic payment order proceedings work similarly.
  2. How and by when should a claim be registered in bankruptcy? A creditor pursues a claim against a bankrupt debtor by registering it. Registration must be submitted within the basic 45-day period after the bankruptcy declaration, electronically using the designated form to the trustee's electronic mailbox; it must be authorised or it will be disregarded. Late registration restricts the creditor's rights; a security right, however, must be properly asserted within 45 days or it will be disregarded. Registration has the same effect on limitation as pursuing the right in court.
  3. When am I entitled to damages, and what is unjust enrichment? Under the general civil-law regime in Section 420 of the Civil Code, the wrongdoer's fault is presumed and compensation covers actual loss and lost profit. Breach of a commercial obligation, however, is subject to the separate liability regime in Section 373 et seq. of the Commercial Code. Unjust enrichment is a benefit obtained without legal grounds and must be returned. Limitation depends on the regime and circumstances: civil-law rules provide a two-year subjective period and specific objective limits, while commercial claims generally have a four-year period.
  4. When and where may we contact a debtor who is a consumer? Anyone recovering a contractual claim in their own name or for a creditor must not visit a consumer or their close persons at home or work without prior express consent. Contact or harassment of any kind is prohibited on Saturdays, days of rest and, on other days, between 18:00 and 08:00 the next day. These prohibitions do not apply to the professional activities of enforcement officers, lawyers and notaries.

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Mgr. Patrik Tulinský, LL.M. Czech and Slovak attorney · SAK 300422 · ČAK 19654

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