1. Introduction

In everyday life and commercial dealings, it is not uncommon for individuals to sign and deliver promissory notes to another party in respect of existing or potential future debts, even though the amount payable, maturity date or other particulars have not yet been completed. Although this practice is often regarded as a practical solution in relationships involving leases, vehicle rentals, sales of goods and debt obligations, it may give rise to significant legal consequences in the event of a dispute.

In this regard, the issues to be considered are not limited to whether a signature on a blank promissory note is legally valid, but also include the circumstances under which the instrument may subsequently be completed and the extent to which the signatory may be held liable.

This is because signing an instrument with incomplete particulars and subsequently completing those particulars in breach of the agreement between the parties are legally distinct matters. This distinction is particularly important in assessing the validity of the instrument and the burden of proving that it has been completed contrary to the parties’ agreement.

Accordingly, this article examines the legal validity of signatures on blank promissory notes, the principles governing their subsequent completion, the limits of the authority to complete such instruments, and the evidentiary requirements applicable to allegations that a promissory note has been completed contrary to the parties’ agreement, in light of the relevant legislation and decisions of the Turkish Court of Cassation.

2. Legal Validity of a Signature on a Blank Promissory Note

Article 776 of the Turkish Commercial Code No. 6102 (the “TCC”) sets out the mandatory particulars that a promissory note must contain. Pursuant to this provision, a promissory note must contain:

“(a) The word ‘promissory note’ or ‘note payable to order’ in the body of the instrument and, where the instrument is drawn in a language other than Turkish, the corresponding expression used in that language;

(b) An unconditional promise to pay a definite sum of money;

(c) The maturity date;

(d) The place of payment;

(e) The name of the person to whom or to whose order payment is to be made;

(f) The date and place of issue; and

(g) The signature of the maker.”

The first paragraph of Article 777 of the same Code provides that, subject to the exceptions set out in its second to fourth paragraphs, “an instrument that does not contain any of the particulars specified in Article 776 shall not be deemed a promissory note.” The remainder of the article sets out exceptions concerning cases in which the maturity date, place of issue or place of payment is not specified.

However, the requirement that all particulars be completed at the time the instrument is issued must be distinguished from the subsequent completion of missing particulars in accordance with the agreement between the parties.

In this respect, Article 680 of the TCC, which also applies to promissory notes pursuant to Article 778(2)(f), provides as follows:

“If a bill of exchange that was incomplete when issued is completed contrary to the agreements made between the parties, non-compliance with those agreements may not be invoked against the holder, unless the holder acquired the bill of exchange in bad faith or was guilty of gross negligence at the time of acquisition.”

This provision permits a negotiable instrument to be issued with certain particulars left incomplete and for those particulars to be completed subsequently. In practice, such instruments are referred to as “blank promissory notes”.

Accordingly, the mere act of signing a promissory note with the amount, maturity date or other particulars left blank does not, in itself, render the instrument invalid. Where the missing particulars are subsequently completed and the instrument contains the mandatory elements prescribed by law, it may qualify as a formally valid negotiable instrument. Nevertheless, completion of the instrument in breach of the agreement between the parties must be assessed separately, particularly in terms of the defenses that may be raised against the liability arising under the instrument.

3. Subsequent Completion of a Promissory Note and the Limits of the Authority to Complete It

The legal recognition of blank promissory notes does not mean that their missing particulars may be completed without any restrictions. Pursuant to Article 680 of the TCC, as set out above, a blank promissory note must be completed in accordance with the agreement between the parties. Therefore, signing and delivering a blank promissory note cannot be interpreted as granting the person holding it unlimited authority to complete the instrument.

The completion agreement is the agreement that determines the circumstances and manner in which the missing particulars of a blank promissory note may be completed. It establishes the legal limits of the authority granted to the holder of the instrument. Although a written completion agreement is not a statutory condition of validity, where the existence or scope of such an agreement becomes contentious, proving the limits within which the authority to complete the instrument was granted becomes particularly important.

This is especially significant in the case of blank promissory notes issued as security. It is important to establish which debt or obligation the instrument is intended to secure and under what conditions it may be completed. Where the scope of the authority to complete the instrument has not been expressly agreed upon, proving that the instrument was subsequently completed contrary to the parties’ agreement may become more difficult.

In this context, depending on the circumstances of the particular case, a blank promissory note issued in connection with a specific debt relationship may be deemed to have been completed in breach of the completion agreement if it is completed for an amount exceeding the agreed sum, if it is completed before the conditions stipulated for its use have been fulfilled, or if the agreed conditions governing its completion are otherwise disregarded.

On the other hand, the fact that the amount, maturity date or other particulars appearing on the instrument have been written by someone other than the signatory does not, in itself, establish that the instrument has been altered or that the completion agreement has been breached. By its very nature, a blank promissory note may be completed after it has been signed, including by another person. Accordingly, the decisive issue is not whether the handwriting on the instrument belongs to different individuals, but whether the instrument was completed within the limits of the authority agreed upon by the parties.

Furthermore, a breach of the completion agreement and the question of whether the instrument retains its status as a negotiable instrument are distinct legal issues. Completion of a blank promissory note contrary to the parties’ agreement does not automatically render the instrument invalid.

Pursuant to Article 680 of the TCC, an allegation that the completion agreement has been breached may be raised against the original payee, who is a party to that agreement. However, such an allegation may be raised against a subsequent holder only if that holder acquired the instrument in bad faith or was guilty of gross negligence at the time of acquisition.

In addition, the first paragraph of Article 687 of the TCC, which also applies to promissory notes pursuant to Article 778(1)(a), provides as follows:

“A person against whom recourse is sought under a bill of exchange may not raise against the holder defenses based on direct relationships with the drawer or a previous holder, unless the holder, in acquiring the bill of exchange, knowingly acted to the detriment of the debtor.”

When these provisions are considered together, it becomes clear that allegations of a breach of the completion agreement and personal defenses arising from the underlying debt relationship are subject to different legal conditions when raised against subsequent holders. Accordingly, the legal position of the original payee and that of subsequent holders must be assessed separately, taking into account the nature of the defense raised and the circumstances in which the instrument was acquired.

In particular, the bad faith or gross negligence criteria under Article 680 of the TCC must be distinguished from the requirement under Article 687 that the holder knowingly acted to the detriment of the debtor.

4. Proving That a Blank Promissory Note Has Been Completed Contrary to the Parties’ Agreement

Where a blank promissory note has been completed contrary to the completion agreement between the parties, one of the decisive issues in resolving the dispute is the evidence by which such non-compliance can be established. Alleging that an instrument was initially signed in blank is legally distinct from proving that it was completed beyond the scope of the authority agreed upon by the parties.

The first paragraph of Article 190 of the Turkish Code of Civil Procedure No. 6100 (the “CCP”) provides as follows:

“Unless otherwise provided by law, the burden of proof rests with the party who derives a legal benefit from the legal consequence attached to the alleged fact.”

Accordingly, as a general rule, a person who acknowledges their signature on a promissory note but alleges that the instrument was completed contrary to the agreement between the parties must prove that allegation. Merely stating that the instrument was initially signed in blank does not, in itself, establish that the authority to complete it was exceeded or that no debt exists in the amount stated on the instrument.

Furthermore, Articles 200 and 201 of the CCP, which govern the requirement to prove certain matters by documentary evidence and the prohibition on using witness testimony to contradict documentary evidence, are relevant to allegations that a completion agreement has been breached. Accordingly, subject to the statutory exceptions, an allegation that a promissory note bearing an acknowledged signature was completed contrary to the agreement between the parties must, as a general rule, be proved by written evidence.

In its decision dated 14 March 2018, numbered E. 2017/897 and K. 2018/464, the General Assembly of Civil Chambers of the Turkish Court of Cassation examined an allegation that a signed blank promissory note had subsequently been completed contrary to the parties’ agreement.

The Court stated that, given the nature of a negotiable instrument as an abstract acknowledgement of debt, the person holding the instrument is not required to prove the underlying debt relationship separately. It also emphasized that an allegation that a promissory note had been completed contrary to the parties’ agreement must, as a general rule, be proved by written evidence.

The Court nevertheless accepted that allegations of fraud could be proved by witness testimony pursuant to Article 203 of the CCP. However, it concluded that the allegations raised in the particular case did not constitute fraud and consequently quashed the decision maintaining the previous judgment, which had relied on witness testimony.

Similarly, in its decision dated 29 March 2017, numbered E. 2016/8978 and K. 2017/2558, the 19th Civil Chamber of the Turkish Court of Cassation held that an allegation that a blank promissory note had been completed contrary to the parties’ agreement must be established by written evidence. As the claimant had failed to submit written evidence supporting the allegation, the Court upheld the judgment dismissing the negative declaratory action.

The 11th Civil Chamber of the Turkish Court of Cassation reiterated this principle in its decision dated 5 March 2025, numbered E. 2024/6473 and K. 2025/1529, emphasizing that an allegation that a signed blank instrument had been completed contrary to the agreement between the parties must be proved by written evidence. As the claimant had failed to substantiate the allegation with evidence admissible under the applicable procedural rules, the Court quashed the judgment granting the negative declaratory action.

Nevertheless, it should not be overlooked that the requirement to prove a claim by written evidence is not absolute and that the exceptions provided for under the CCP may apply depending on the circumstances of the particular case. In this regard, the first paragraph of Article 202 of the CCP provides:

“Where documentary evidence is mandatory, witnesses may be heard if there is prima facie documentary evidence.”

Accordingly, contracts between the parties, correspondence demonstrating the purpose for which the promissory note was issued, payment records and other documents may be relevant to proving the existence and scope of the completion agreement, depending on their legal nature. However, not every document automatically qualifies as prima facie documentary evidence; the conditions set out in Article 202 of the CCP must be satisfied in the circumstances of the particular case.

In particular, where a blank promissory note has been issued as security, the nature of the underlying debt relationship, the terms of the agreement between the parties and the circumstances in which the instrument was delivered are important for evidentiary purposes. Assessments based on the ordinary course of events must also be considered in conjunction with the circumstances of the particular case and the evidence submitted. Such assessments should not, in themselves, be regarded as automatically displacing the requirement to prove matters contrary to the contents of an acknowledged instrument by written evidence.

Furthermore, proving that a promissory note has been completed contrary to the parties’ agreement must be distinguished from disputing the authenticity of the signature appearing on it. Where the signatory acknowledges that the signature belongs to them, the dispute centers not on the authenticity of the signature but on the authority under which, and the circumstances in which, the instrument was completed. Therefore, establishing that the handwriting on the instrument belongs to someone other than the signatory does not, in itself, prove that the completion agreement has been breached.

In our view, the most important evidentiary consideration in disputes arising from blank promissory notes is the ability to establish, through concrete evidence, the parties’ common intention at the time the instrument was issued. The fact that the instrument was delivered on the basis of a relationship of trust does not eliminate the need to prove the legal limits of that relationship.

Consequently, although a written completion agreement is not a statutory condition of validity, specifying in writing the purpose for which the instrument is issued, the amount for which it may be completed and the conditions under which it may be used is important from an evidentiary perspective and may help prevent disputes in the future.

5. Conclusion and Assessment

Signing a blank promissory note does not, in itself, render the instrument invalid under Turkish law. Nevertheless, the legal validity of a blank promissory note does not confer upon the person holding it unlimited authority to complete the instrument independently of the agreement between the parties.

In disputes arising from blank promissory notes, the formal validity of the instrument, the scope of the authority to complete it and whether that authority has been exercised in accordance with the parties’ agreement must be assessed separately. In particular, the importance of written evidence in substantiating allegations that an instrument has been completed contrary to the parties’ agreement, together with the limitations on the defenses that may be raised when the instrument is transferred to subsequent holders, increases the legal risks associated with signing blank promissory notes.

Accordingly, to prevent potential legal disputes, promissory notes should, wherever possible, be signed only after all mandatory particulars have been completed. Where the issuance of a blank promissory note is preferred, the purpose for which it is delivered, the scope of the authority to complete it and the conditions under which it may be used should be clearly documented in writing.

References

1. Günay, Erhan, “Blank Promissory Notes (Article 680 by Reference to Article 778(2)(f) of the Turkish Commercial Code)”, Terazi Hukuk Dergisi, Vol. 13, No. 144, August 2018, pp. 108–112.
2. Bingöl, Fatma İtır, “The Need to Rely on the Presumption of the Ordinary Course of Events in Proving That a Blank Promissory Note Issued as Security Has Been Completed Contrary to the Completion Agreement, and an Example from Practice Concerning Lease Agreements”, Yaşar Hukuk Dergisi, Vol. 8, Nos. 1–2, 2026, pp. 1–34.
3. General Assembly of Civil Chambers of the Turkish Court of Cassation, decision dated 14 March 2018, E. 2017/897, K. 2018/464.
4. 19th Civil Chamber of the Turkish Court of Cassation, decision dated 29 March 2017, E. 2016/8978, K. 2017/2558.
5. 11th Civil Chamber of the Turkish Court of Cassation, decision dated 5 March 2025, E. 2024/6473, K. 2025/1529.