You overpaid in a ZCP transaction. Do you know who is entitled to the refund? Hint: not you.

You overpaid in a ZCP transaction. Do you know who is entitled to the refund? Hint: not you.

This is one of those issues that, at first glance, looks like an accounting problem. An overpayment. An error in the schedule. The difference needs to be refunded. Simple? Not quite.

If you are selling or buying an organized part of an enterprise (ZCP) and settling the seller’s liabilities through a payment order — the mechanism provided for in Article 921¹ of the Civil Code — an overpayment resulting from an incorrect schedule of liabilities does not return by the same route it came. Intuition suggests: “since the money came from the buyer, it should be refunded to the buyer”. That answer is wrong. The refund should go to the ZCP seller, even though the buyer physically made the transfer.

In this article, I will explain why this is the case, what risks are created by a “shortcut” settlement, and what to do — step by step — to remedy or prevent the situation.

Terms you need to know before reading further

Before we get to the heart of the matter, here are a few terms that will appear repeatedly:

How a payment order works in a ZCP sale and why an overpayment “returns” by a different route

Three parties, two legal relationships

A ZCP sale in which liabilities are settled through a payment order involves three parties:

1. Seller (the person issuing the payment order) — sells the ZCP and authorizes the buyer to pay its creditors.
2. Buyer (the person instructed to pay) — buys the ZCP and, instead of paying the entire price to the seller, pays part of it directly to the seller’s creditors.
3. Creditor (the recipient of the payment order) — the seller’s counterparty whose receivables are “included” in the transaction price.

In its judgment I CSK 486/15, the Supreme Court confirmed that carrying out a payment order may simultaneously discharge obligations arising from both the cover relationship and the underlying relationship. In turn, in judgment IV CSK 537/19, the Supreme Court described a payment order as a technical act that does not independently confer a benefit.

What happens when the schedule of liabilities is incorrect

Imagine the following situation: your SaaS company sells a B2B product as a ZCP. The price “includes” liabilities owed to an API provider, which are settled through a payment order. After closing, it turns out that one invoice listed in the schedule had already been paid and another was a pro forma invoice rather than an invoice. The buyer paid the creditor more than it should have.

Who receives the refund?

The answer follows from the legal structure of the payment order. A claim for the return of an undue performance (Article 410 of the Civil Code) belongs within the relationship in which the legal basis was absent. Since the seller’s debt to the creditor was lower than stated in the schedule, the absent legal basis concerns the underlying relationship (seller–creditor). The creditor refunds the excess to the seller. Not the buyer.

| Who pays | Who receives | Legal relationship | Is there an overpayment here? |
|:———-|:————-|:—————-|:———————|
| Buyer | Creditor | Performance of the payment order (technical cash flow) | No — the buyer followed the instruction |
| Seller → Creditor | Underlying relationship | Yes — the seller’s debt was lower than declared |
| Buyer → Seller | Cover relationship | Depends on the wording of the ZCP sale agreement |

This is counterintuitive, but logical. The buyer carried out the payment order in accordance with the agreement. It was not required to verify whether the schedule of liabilities was correct — it relied on the transaction document. The excess arose within the seller–creditor relationship, so that is where it should be settled.

Five risks created by a “shortcut” settlement of an overpayment

Companies often try to settle an overpayment “by taking a shortcut” — the creditor transfers it directly to the buyer, without an amendment and without updating the documentation. This works operationally, but creates specific problems.

a) Risk of double settlement

The creditor claims that it settled with the seller. The buyer claims that it settled with the creditor. During an audit, a dispute, or subsequent due diligence, no one can explain the basis on which the adjustment payment was made specifically to the buyer. The seller may independently seek a refund from the creditor — resulting in a three-party dispute.

b) Lack of documentary basis

A transfer made without an amendment must be documented after the fact. During an investor audit, there is no good answer to the question “what is the basis for this transfer?”. This undermines the company’s credibility in the eyes of a potential investor or buyer.

c) Tax liability arising from a prematurely issued invoice

Issuing an invoice against a pro forma invoice “just in case” creates a tax liability. It then has to be corrected — and Article 106j(1) of the VAT Act requires a corrective invoice, not a corrective note. A corrective note cannot be used to change the price or the taxable amount.

d) Unilateral amendment of the schedule

Changing the schedule of liabilities without the knowledge and consent of the other party to the transaction is a unilateral amendment. It is not legally binding. It may lead to the entire settlement being challenged.

e) Relationship risk

A delay in identifying and correcting the error complicates the relationship with the creditor — especially if it is a supplier or partner whose cooperation was intended to continue after the transaction.

Remedial sequence — what to do when the schedule of liabilities proves incorrect

The order of steps matters. Making the transfer before signing the amendment reverses the proper logic — first you need a documentary basis, then the financial flow.

Step 1: verify the schedule of liabilities

Have the accounting team review the schedule item by item against the source documents — invoices, transfer confirmations, and pro forma invoices. Record the results in a table:

Step 2: notify the other party to the transaction

Even if the error occurred on your side and the amount seems small — notify the other party. A unilateral correction is not binding. A ZCP sale is a bilateral transaction, and every change to the schedule requires both parties’ consent.

Step 3: prepare and sign an amendment

The amendment should cover both agreements: the ZCP sale agreement and the payment order agreement. It must include:

1. A corrected schedule of liabilities referring to specific items.
2. The new amount covered by the payment order.
3. The method for settling the excess — a refund to the seller’s account or its application toward another specifically identified liability.
4. The deadline for making the adjustment payment.

Step 4: suspend invoicing

Do not issue invoices against pro forma invoices included in the schedule until the amendment determines whether and to what extent they are covered by the settlement. An invoice issued “just in case” creates a tax liability that must later be corrected.

Step 5: make the adjustment payment

Only after the amendment has been signed — not the other way around. A transfer made before the amendment will still have to be described in the documents, but only after the fact, which complicates the audit trail.

Contact us — we will help you prepare the amendment and put the settlement in order.

Why Article 411(1) of the Civil Code does not prevent the overpayment from being refunded

A common question is: “if I paid knowing how much I was paying, can I still request a refund?”

Article 411(1) of the Civil Code states that the return of a performance cannot be demanded if the person making it knew that they were not obliged to do so. But this refers to knowledge that no obligation existed, not knowledge of the amount being transferred.

A mistake as to the existence of an obligation — where all parties believed the schedule to be correct — does not constitute knowledge that no debt existed. The parties acted on the assumption that the schedule reflected the actual position. It was only after the transaction closed that this proved not to be the case.

Nor is the excess automatically:

1. An advance payment toward future liabilities owed to the same creditor — without an express contractual provision.
2. An adjustment to the ZCP price — that is an entirely different legal relationship.
3. A gift — there was no intention to make a gift.

Unless deliberately addressed in an amendment, the excess remains an undue performance within the meaning of Article 410 § 2 of the Civil Code.

Limitation period — do not delay sending a demand for payment

A claim for the return of an undue performance is a claim with no specified due date. It becomes due after the debtor has been called upon to pay (Article 455 of the Civil Code). The limitation period begins on the date when the claim would have become due had the demand been made at the earliest possible time — Article 120 § 1 of the Civil Code.

The date on which the error in the schedule was discovered is not the statutory starting date of the limitation period — it is relevant only as evidence. However, the sooner you send a demand after discovering the error, the lower the risk that the claim will become time-barred before you enforce it.

Confirmation of this rule can be found in the judgment of a court of general jurisdiction in case I C 34/22, which confirms the three-year limitation period for business-related claims.

How to protect yourself in the future — an adjustment clause and pre-signing verification

A single sentence containing an adjustment clause in the agreement can eliminate the need to negotiate an amendment later. The principle of freedom of contract (Article 353¹ of the Civil Code) allows the parties to define a mechanism for adjusting the price after the transaction closes.

What an adjustment clause should include

1. Definitions of the items subject to adjustment — working capital, net debt, cash, and trade payables.
2. Measurement date — the specific date as of which the liabilities are determined (e.g. the transaction closing date).
3. Hierarchy of accounting principles — the standards according to which the settlement is prepared.
4. Procedure for preparing and delivering the settlement statement — who prepares it, by what deadline, and in what form.
5. Deadlines for objections — how many days the other party has to submit comments.
6. Expert’s authority — who resolves disputes over amounts (e.g. a statutory auditor appointed by both parties).
7. Allocation of the expert’s costs.
8. Payment deadline for the difference and default interest.

There is no publicly available official template for such a clause for the Polish M&A market — but the above elements follow from the principle of freedom of contract and the most common causes of post-closing disputes.

Three preventive rules

1. The schedule of liabilities must undergo accounting verification before the agreement is signed — with a balance determination date and the position as of a specific date. A list of “outstanding invoices” without a reference date is an invitation to error.
2. Sign the payment order agreement at the same time as the ZCP sale agreement — with both referring to the same specifically identified appendix containing the schedule of liabilities. Misalignment between the two agreements (different appendices or different dates) is the most common cause of this problem.
3. Do not issue invoices against pro forma invoices included in the schedule until the agreement determines whether and to what extent they are covered by the settlement.

Tax consequences — what you need to know about VAT and CIT

The sale of a ZCP is excluded from VAT under Article 6(1) of the VAT Act. The mere refund of an amount received but not due does not constitute a separate transaction subject to VAT, provided that the transaction was correctly classified.

The CIT implications depend on whether the refunded amount was previously recognized as income due. There is no single universal answer here — each set of facts requires a separate analysis. It is worth consulting a tax adviser before making the adjustment payment.

Before you sign the schedule of liabilities — give us 2 hours to verify it

An amendment after the event costs more than verification before signing. Lawyers’ and accountants’ time, negotiations with the other party, document corrections, and the risk of a dispute — all of this can be reduced through a single transaction consultation before closing.

We support founders, management boards, and CFOs of technology companies in ZCP sale and purchase transactions — from structuring the settlement and preparing schedules of liabilities to adjustment clauses and payment order agreements.

If you have already closed the transaction and want to check whether the settlement is correct — we will conduct a post-closing review of the documentation and identify what needs to be corrected.

Contact us — we will put the settlement in order before the problem grows.

Frequently asked questions

I am selling a product line as a ZCP — do I need to verify the schedule of liabilities with the accounting team before signing, or is a report from the system sufficient?
A report from the accounting system is a starting point, not a finished schedule. Systems confuse pro forma invoices with invoices, fail to account for payments in progress, and do not understand the transaction context. The schedule must undergo accounting verification, with a balance determination date and the position as of a specific date. Otherwise, you risk discovering after closing that some items had already been paid or did not constitute liabilities at all.

I bought a ZCP and overpaid through a payment order — should I receive the refund, or should the seller?
Under the payment order mechanism, the excess concerns the underlying relationship, meaning the seller–creditor relationship. The creditor refunds the overpayment to the seller, not the buyer — even though the buyer physically made the transfer. The buyer carried out the payment order in accordance with the agreement. If you want to change this and settle “by taking a shortcut”, you need an amendment that provides a documentary basis for a different flow of funds.

What if the creditor has already spent the overpaid amount — can I still demand a refund?
Yes. The creditor’s spending of the amount does not extinguish the claim for the return of an undue performance. The creditor may argue that the enrichment has ceased to exist (Article 409 of the Civil Code), but must demonstrate that it should not have expected an obligation to make a refund. In an M&A transaction where the schedule of liabilities is an integral part of the agreement, this is difficult to prove.

Can I agree in advance in the contract that any excess will automatically be applied toward subsequent invoices from the same creditor?
Yes — provided that you state this expressly in the agreement or amendment. Without such a provision, the excess remains an undue performance. Automatic application toward future liabilities does not follow from any statutory provision — it requires a deliberate decision by the parties documented in the agreement.

Does the absence of an adjustment clause in the agreement mean that I have to negotiate a full amendment every time the schedule does not match?
In principle, yes. Without an adjustment clause, you have no contractual mechanism for settling differences. Each discrepancy requires a separate agreement between the parties — which means negotiations, an amendment, and time. This is why it is worth including an adjustment clause in the standard ZCP sale agreement template. One sentence can save weeks of post-closing negotiations.

What if both parties want to settle “by taking a shortcut” and the creditor transfers the money directly to the buyer — is an ordinary email confirmation sufficient?
No. An email confirmation is not a substitute for an amendment to the agreement. During a tax audit, a dispute, or due diligence, there will be no document justifying the flow of funds. The creditor claims that it settled with the seller, while the buyer claims that it settled with the creditor — creating a risk of double settlement. Even if the parties want to simplify the flow, they need an amendment that provides a legal basis for it.