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Acquiescence in Trade Mark Law: Different Rules for Invalidity and Infringement

Markada Sessiz Kalma: Hükümsüzlük ve Tecavüz Davalarında Farklı Kurallar
Authors
Uğurcan TekinAlican TekinBeyza ErdemirUğurcan Tekin · Alican Tekin · Beyza Erdemir
Published5 October 2026
Reading time22 min
← All Insights
CategoryTrademark
Published5 October 2026
Authors
Uğurcan TekinPartner
Alican TekinPartner
Beyza ErdemirAttorney at Law
In this article
AcquiescenceIPC Article 25(6)Invalidity actionInfringement action
SummaryÖzet

This article has been prepared with a view to setting out the respects in which loss of rights through acquiescence in trade mark law differs as between invalidity actions and trade mark infringement actions. The article first describes the decisions of the 11th Civil Chamber of the Court of Cassation on the starting point of the five-year period in invalidity actions and the divergence between those decisions, together with its most recent decision, the decision of the 11th Civil Chamber of the Court of Cassation dated 4 June 2026, E. 2026/3054, K. 2026/3267. It then examines the criteria applicable in infringement actions and shows that even where loss of rights through acquiescence is not accepted in an invalidity action, the same silence may have consequences in an infringement action.

Key takeaway · Kilit sonuç

The Chamber’s decisions on when the five-year invalidity period begins diverge; under the most recent, it does not run before registration, yet earlier silence may count against an infringement claimant under good faith.

The same silence, two actions, two rulesFigure 1
Invalidity actionIPC Art. 25(6) · five years
Infringement actionTCC Art. 2 · principle of good faith
Unfair competitionTCC Art. 2
Loss of rights through acquiescenceknowledge · time · good faith · investment · proof of use as a trade mark

Put simply, loss of rights through acquiescence means that a person who knows, or ought to know, that their right is being infringed, yet takes no step whatsoever for a long period, cannot subsequently bring proceedings against the other party who has invested in reliance on that silence. The rationale behind the doctrine is that a right holder who remains silent for a long time creates reliance on the other side, and that conduct inconsistent with that reliance will not be protected by the legal order.

In trade mark disputes, the doctrine arises in two distinct types of action. In an invalidity action, the claimant seeks cancellation of a trade mark registration entered on the register in the defendant’s name. In an infringement action, by contrast, the claimant seeks to stop the defendant’s use of a sign in the course of trade. The target of the first action is the entry on the register; the target of the second is use in the market. Loss of rights through acquiescence may be raised in both actions, but it is not governed by the same rule in each.

For invalidity actions, the rule is expressly laid down in Article 25(6) of the Industrial Property Code No. 6769 (“IPC”) and provides for a five-year period. For infringement actions, however, the IPC contains no provision, and the matter is resolved under the principle of good faith in Article 2 of the Turkish Civil Code No. 4721 (“TCC”) and the case law of the Court of Cassation. This difference makes it possible for the same silence to produce no consequence in one action and yet to produce consequences in the other.

01
The Rule in Invalidity Actions: The Five-Year PeriodHükümsüzlük Davasında Kural: Beş Yıllık Süre

In invalidity actions, loss of rights through acquiescence is governed by statute. Where the holder of an earlier right has not objected to the use of a later trade mark for five years, it cannot seek invalidity of that trade mark on the basis of its own earlier right.

Statutory provisionKanundaki düzenleme

Article 25(6) of the IPC reads as follows: “Where the proprietor of a trade mark, knowing or being in a position to know that a later trade mark is being used, has remained silent in respect of that situation for five successive years, it may not rely on its trade mark as a ground for invalidity unless the registration of the later trade mark was made in bad faith.”

The provision contains four elements: the later trade mark is being used; the earlier right holder knows or ought to know of that use; the silence has lasted for five uninterrupted years; and the registration of the later trade mark was not made in bad faith. In its decision dated 24 September 2025, E. 2025/840, K. 2025/5647, the 11th Civil Chamber of the Court of Cassation (“the Chamber”) stated: “The five-year period laid down in the said provision is a forfeiture period.” If the later registration was made in bad faith, the period does not bar the invalidity claim.

The provision contains no period tied to the date of application, publication or registration. It ties the period to the moment at which the earlier right holder knew or ought to have known that the later trade mark was being used. It is on this point that the debate in practice is focused: where the later trade mark was also used before registration, the question is whether the five-year period begins to run from the date on which that use became known or, at the earliest, from the date of registration.

02
The Start of the Period: The Chamber’s Divergent DecisionsSürenin Başlangıcı: Dairenin Farklı Yöndeki Kararları

In four decisions rendered in 2025 and 2026, the 11th Civil Chamber of the Court of Cassation has answered this question in two different directions. Of these, the decisions of 24 September 2025 and 4 June 2026 belong to the same file. Three of the decisions state that use prior to registration must be taken into account, whereas the most recent decision in time upholds a decision to insist which accepted that the period does not run before registration.

Decisions Taking Pre-Registration Use into AccountTescil Öncesi Kullanımı Dikkate Alan Kararlar

In its decision dated 19 March 2025, E. 2024/3476, K. 2025/1973, the Chamber reversed a regional court of appeal decision that had started the five-year period from the date of registration. The decision states: “what is sanctioned is the silence for five years of the interested party who knows of the ground for invalidity, as from the date on which the trade mark whose invalidity is sought began to be used, not as from its registration”. In that case, the trade mark whose invalidity was sought was registered on 26 January 2015, and the action was brought on 24 January 2020, two days before the expiry of five years from registration. Taking into account that the claimant had opposed the application on 14 October 2013 and that the trade mark had been used in 2014, the Chamber concluded that loss of rights through acquiescence had occurred. On this decision, the fact that the action was brought within five years of registration is not sufficient in itself.

In its decision dated 30 March 2026, E. 2025/4864, K. 2026/1820, the Chamber likewise reiterated that dates of use prior to registration must be taken into account, and upheld a decision rejecting an invalidity claim on the ground of acquiescence. In that case, the defendant held another trade mark bearing the same dominant element, registered in 2005, and it was also apparent that the defendant had been using the name in a domain name since 2000. In the same decision, the Chamber characterised the Regional Court of Appeal’s reasoning calculating the five-year period from the application date as “erroneous reasoning”, but did not regard it as affecting the outcome.

The Most Recent Decision: 4 June 2026Son Karar: 04.06.2026

On one side of the dispute underlying the Chamber’s most recent decision is the owner of a business who had not registered as a trade mark the name used for its food and beverage services. This party, the claimant, maintained that the name had been in use since 1988 and that the claimant had taken over the business bearing the name in 2011. On the other side is the defendant, which had registered the same name as a trade mark in its own name under two registrations whose numbers bear the years 2015 and 2018. The defendant, for its part, argued that it had itself been using the name in the same sector since 1973. In 2020, the claimant sought a declaration of invalidity of the defendant’s trade marks and a declaration that its own use did not infringe the defendant’s trade mark rights and did not constitute unfair competition.

The Bakırköy 1st Civil Court of Intellectual and Industrial Property Rights allowed the claim, and the 44th Civil Chamber of the Istanbul Regional Court of Appeal, by its decision dated 19 December 2024, reached the same result on amended reasoning. By its decision dated 24 September 2025, the 11th Civil Chamber of the Court of Cassation reversed that decision in favour of the defendant. The reversal decision stated, with reference to legal scholarship: “In invalidity actions, it is not an absolute rule that the period applicable to loss of rights through acquiescence begins to run from the date of registration. If the trade mark whose invalidity is sought was used before the date of registration, the dates of use prior to registration must also be taken into account.” The Chamber held that the conditions for loss of rights through acquiescence had to be examined in light of the defendant’s defence that it had been using the name since 1973.

A regional court of appeal is not bound to comply with a reversal decision of the Court of Cassation; it may insist on its earlier judgment, and such insistence is referred to as a decision to insist. In the present case, the Regional Court of Appeal did not comply with the reversal decision and insisted on its earlier judgment. The reasoning of the decision to insist rests on two limbs. On the legal limb, the words “unless the registration of the later trade mark was made in bad faith” in Article 25(6) of the IPC presuppose that the trade mark in respect of which silence was kept is a registered trade mark. On this point, the court concluded that “an action seeking invalidity of a trade mark used without registration cannot be brought, and carrying the five-year forfeiture period for bringing an action back to a date before registration would result in the period running before any right of action had arisen”, and accepted that the five-year period had not expired. On the factual limb, the 1973 business licence relied on by the defendant was registered in the names of other persons, and it had not been proven that the defendant’s business was a continuation of that business.

Pursuant to Article 373(5) of the Code of Civil Procedure No. 6100, the decision to insist was first examined by the Chamber whose decision had been resisted. In its decision dated 4 June 2026, the 11th Civil Chamber of the Court of Cassation upheld the decision to insist on the ground that “since it is understood that there is no error in the decision to insist rendered by the Regional Court of Appeal, all of the grounds of appeal of the defendant’s counsel are unfounded”. The decision was rendered finally and unanimously. Under that provision, if the Chamber finds the decision to insist well-founded, it corrects its own decision; if not, it refers the file to the General Assembly of Civil Chambers of the Court of Cassation (“the General Assembly”). The Chamber did not refer the file to the General Assembly and, as regards this file, departed from its own reversal decision. As a result, the defendant’s trade marks were declared invalid, and it was also established that the claimant’s use did not constitute infringement or unfair competition.

In plain termsSade anlatımla

An invalidity action is brought to cancel a registration on the register. The thinking behind the decision to insist is this: where there is no registration, there is no entry to cancel; and time cannot run for an action that could not have been brought. In its most recent decision, the Court of Cassation upheld this decision to insist. Under the decision to insist thus upheld, the five years begin to run at the earliest on the date of registration.

DateDecisionOutcome as regards the start of the period
19.03.2025ReversalThe date on which the use was known, not the date of registration, is decisive
24.09.2025Reversal (file underlying the most recent decision)Dates of use prior to registration are also taken into account
30.03.2026UpheldDates of use prior to registration are also taken into account
04.06.2026Decision to insist upheldUnder the decision to insist upheld, the period does not run before registration
The chamber’s decisions on the start of the period
03
The Significance of the Most Recent Decision and RecommendationsSon Kararın Anlamı ve Öneriler

The most recent decision in time upheld a decision to insist which accepted that the period cannot start to run on a date preceding registration. The Chamber reached this outcome by departing from the reversal decision it had rendered in the same file, which had required pre-registration use to be taken into account. In this respect, the decision strengthens the view that, in invalidity actions, the five-year period is to be calculated from the date of registration.

The limits of the decision must be stated with equal clarity. First, the Chamber’s own reasoning consists of a single sentence, and it does not separately explain which of the legal and factual limbs of the decision to insist it adopted. Since the defendant’s pre-registration use could not be proven, the outcome of upholding can also be explained by the factual limb. Second, the decision is not a decision of the General Assembly but a decision of the Chamber finding the insistence well-founded. Third, the decision contains no statement that the Chamber has expressly departed from its decisions of 19 March 2025 and 30 March 2026.

In our assessment, on the basis of the most recent decision, the five-year period in an invalidity action does not begin to run before the date of registration. That said, the Chamber’s earlier decisions remain in place, and it is too early to say that practice has become consistent. An earlier right holder contemplating an invalidity action would therefore be prudent not to wait for five years to elapse from the date of registration, but to bring the action before five years have elapsed from the date on which it learned of the other party’s use or opposed the other party’s application. For the proprietor of a later trade mark wishing to protect its registration, by contrast, it is important to retain documents showing that the pre-registration use was its own and was known to the other party. In the case underlying the most recent decision, the defendant’s claim of use dating back to 1973 was disregarded because the licence was in the names of other persons and the continuity of the business could not be shown.

In plain termsSade anlatımla

Neither publication of the application nor registration appears in the Code as a date that automatically starts the period. Under the most recent decision, the period does not run before registration; under the earlier decisions, however, use prior to registration is also taken into account. Given this difference between the decisions, the safe course is to act within five years of learning of the use, without waiting for the date of registration.

04
Differences in Infringement ActionsTecavüz Davasında Farklılıklar

The position is different in an infringement action. Where the proprietor of an earlier trade mark brings an action to stop the use against a person who has been using the sign for years, Article 25(6) of the IPC does not apply, since that provision governs invalidity claims only. In the decision of the 11th Civil Chamber of the Court of Cassation dated 24 March 2025, E. 2024/3651, K. 2025/2081, it was stated that the IPC contains no specific provision on loss of rights through acquiescence in infringement actions and that the principle is founded on Article 2 of the TCC.

Statutory provisionKanundaki düzenleme

Article 2 of the TCC reads as follows: “Everyone must comply with the principle of good faith in exercising their rights and performing their obligations. The legal order does not protect the manifest abuse of a right.”

The Benchmark PeriodSürenin Ölçüsü

No statutory period applies in infringement actions. In its decision dated 25 October 2022, E. 2021/3291, K. 2022/7375, the 11th Civil Chamber of the Court of Cassation expressed the benchmark as follows: “According to the settled practice of our Chamber, where the trade mark proprietor has remained silent in the face of serious use for five years by third parties of a trade mark registered in another’s name for at least five years, and investment has been made in that trade mark, the subsequent bringing of an infringement action by the right holder on the basis of its trade mark right is contrary to the principle of good faith under Article 2 of the TCC”. In that case, the defendant relied not on a trade mark registration but on having used the sign on its products since 2010. The Chamber did not hold the defence to be well-founded; rather, it treated as a ground for reversal the fact that infringement had been established without any assessment, favourable or unfavourable, of the acquiescence defence.

According to the Chamber’s view as recounted in the decision of the General Assembly dated 10 December 2025, E. 2024/376, K. 2025/798, however, “it is not possible to set a definitive period after which silence will lead to loss of rights”, and the period is determined according to the particular circumstances of the case and the principle of good faith. Read together, the two decisions show that five years is not a statutory period but a benchmark used in practice. Accordingly, the fact that five years have not elapsed does not, by itself, provide the trade mark proprietor with any assurance.

Conditions and ProofKoşullar ve İspat

In the same decision, rendered by majority in an action brought while Decree-Law No. 556 was in force, the General Assembly set out the conditions of the principle. The decision states: “Where the proprietor of a trade mark, without justified cause, has for a long time failed to exercise its rights arising from infringement of its trade mark and has thereby given rise to the belief that it will not exercise those rights against the continuing uses of the sign in the future, it should no longer be able to exercise that right.” According to the decision, the right holder must have known of the use and nevertheless remained silent for an appreciable period, the silence must not be based on a justified cause such as force majeure, and the person using the sign must be in good faith. Where the user is in bad faith, there can be no loss of rights through acquiescence. Indeed, in its decision dated 3 April 2024, E. 2022/6764, K. 2024/2755, the 11th Civil Chamber of the Court of Cassation held that the use and registration of the same name by the defendant, a former employee of the claimants, was in bad faith, and concluded that “uses in bad faith will not give rise to loss of rights through acquiescence”.

The decision emphasised two further points. First, “the defence that no action may be brought by reason of acquiescence is not a plea but an objection”; in other words, where bringing the action clearly amounts to an abuse of right and this is apparent from the case file, the court takes it into account of its own motion. This does not remove the need to submit the facts and evidence underlying the defence to the file in full. Second, proof of the defence depends on establishing concretely the date on which use as a trade mark began. The General Assembly characterised the use appearing on a tax registration certificate, an administrative sanction report and invoices not as use as a trade mark but as use of a trade name, and did not consider it sufficient to prove the acquiescence defence.

The consequence of loss of rights through acquiescence is also limited. In the words of the same General Assembly decision, “In loss of rights through acquiescence, the right is not extinguished generally; it is merely that the enjoyment of that right by the person or persons whose conduct was met with silence must be tolerated.” In other words, the claimant’s trade mark remains valid and simply cannot be asserted against the use in respect of which silence was kept.

ConditionMeaningPoints to note on proof
KnowledgeThe right holder knows or ought to know of the useSame sector, same region, correspondence, a cease-and-desist letter or an opposition to an application show the right holder’s knowledge
TimeAn appreciable period; in practice, a five-year benchmarkThe date on which use as a trade mark began should be shown by documents
Absence of justified causeThe silence is not based on a cause such as force majeureThe justified cause must be proven
Good faithThe user was not in bad faith when choosing and using the signChoosing the same sign with knowledge of the earlier trade mark may be held against the user; in the case of bad faith, the defence will not be entertained
Investment (an element carrying weight in the assessment)Effort and capital have been invested in the signSignage, packaging, advertising, promotional and sales documents
Conditions of the acquiescence defence in an infringement action
Silence Without Consequence in Invalidity May Have Consequences in InfringementHükümsüzlükte Sonuç Doğurmayan Sessizlik Tecavüzde Sonuç Doğurabilir

The essential difference between the two actions lies in the fact to which the period is tied. In an invalidity action, according to the decision to insist upheld by the most recent decision, the period does not run before registration. In an infringement action, by contrast, the period is tied not to an entry on the register but to the actual use of the sign and the right holder’s tolerance of that use. Accordingly, while the years during which the sign was used without registration may not be taken into account in an invalidity action, they lie at the centre of the assessment in an infringement action.

The consequence is as follows: even if loss of rights through acquiescence is not accepted in an invalidity action because the later trade mark has only recently been registered, the right holder’s long silence before registration may be assessed under Article 2 of the TCC in an infringement action between the same parties. In our assessment, the file underlying the most recent decision also bears traces of this distinction. As recounted in the Chamber’s decision of 24 September 2025, the court of first instance, in holding that the unregistered user’s use did not constitute infringement, gave the following additional reasoning: “since, even if the claimant’s status as the true right holder is not accepted, loss of rights through prolonged acquiescence will in that case arise in view of its serious and uninterrupted use spanning many years”. Since the Regional Court of Appeal based its outcome on the claimant’s rights arising from prior use, this additional reasoning has not been separately assessed by the higher courts; it nonetheless shows that the assessments in the two actions proceed independently of one another.

In our assessment, this distinction may in practice lead to two outcomes arising side by side. Where a sign has been used without registration for many years and is then registered, and the proprietor of an older trade mark brings an action for invalidity and infringement before five years have elapsed from registration, the invalidity claim will, under the decision to insist upheld by the most recent decision, be regarded as brought within time, and the later registration may be declared invalid. In the same action, the party using the sign will be unable, under Article 155 of the IPC, to rely on its later registration as a defence to the infringement claim, but will be able to argue under Article 2 of the TCC that no objection was raised to its long-standing use, which began before registration. If the conditions of that defence are proven, the earlier trade mark proprietor may have the other party’s registration cancelled, yet may be unable to obtain an order stopping the use to which it raised no objection for years. Since cancellation of the registration and the stopping of the use are separate claims, the acceptance of one does not mean that the other will also be accepted. We have not come across a decision of the Court of Cassation setting out this outcome within a single action; the assessment rests on a combined reading of the decisions discussed above.

Acceptance of the acquiescence defence does not afford the party using the sign unlimited protection. In our assessment, the protection is confined to the use in respect of which silence was kept; extending the sign to new products, or to a new get-up closer to the earlier trade mark, may not benefit from the same protection. The earlier trade mark remains valid, and acceptance of the defence does not confer a new trade mark right on the user; under Article 7(1) of the IPC, trade mark protection is obtained through registration.

In plain termsSade anlatımla

Cancellation of the registration and the stopping of the use are two separate claims. A party that has used the sign for years but registered it only recently may lose its registration. If, however, the other party raised no objection for years and the user is in good faith, the use may continue.

Invalidity actionInfringement action
ClaimCancellation of the registration on the registerStopping the use in the market
BasisIPC Article 25(6)TCC Article 2 and Court of Cassation case law
TimeFive yearsNo statutory period; in practice, a five-year benchmark
Start of the periodUnder the decision to insist upheld by the decision of 4 June 2026, it does not run before registration; under the decisions of 19 March 2025 and 30 March 2026, pre-registration use and the right holder’s knowledge are taken into accountCommencement of use as a trade mark and the right holder’s knowledge; registration is not required
Period of unregistered useUnder the decision to insist upheld by the most recent decision, does not set the period runningTaken into account in the assessment
Effect of bad faithIf the later registration was made in bad faith, the period is no barIf the user is in bad faith, the defence will not be entertained
OutcomeThe earlier right cannot be relied on as a ground for invalidityThe use met with silence cannot be stopped; the trade mark remains valid
Loss of rights through acquiescence in the two actions
05
Assessment and ConclusionGenel Değerlendirme ve Sonuç
““Silence before registration may not start the period in an invalidity action, yet the same silence may confront the claimant in an infringement action through the principle of good faith; what counts is how time is used and documented.””

Loss of rights through acquiescence is shaped by statute in invalidity actions and by the principle of good faith and the case law of the Court of Cassation in infringement actions. The decisions of the 11th Civil Chamber of the Court of Cassation on the starting point of the five-year period in invalidity actions do not point in the same direction. In its decisions of 19 March 2025, 24 September 2025 and 30 March 2026, the Chamber stated that use prior to registration must be taken into account, whereas in its most recent decision of 4 June 2026 it upheld a decision to insist which accepted that the period does not run before registration. Whether this outcome becomes settled practice will become clear from subsequent decisions.

In an infringement action, the period is not fixed by statute and is not tied to the date of registration. What is decisive is the right holder’s prolonged inaction despite knowing of the use, the user’s good faith and the investment made in the sign. Accordingly, even if loss of rights through acquiescence is not accepted in an invalidity action, the same silence may be assessed under the principle of good faith in an infringement action, and a person who has used a sign for many years may rely on this defence in an infringement action brought by the proprietor of an older trade mark. In such a case, the subsequent registration may be declared invalid, while the use that began before registration may continue.

In our assessment, when the two actions are considered together, the same conclusion emerges for both parties: what is decisive is how time has been used and how this has been documented. For the trade mark proprietor, it is important to monitor the market regularly and to act without delay once a similar use comes to its attention. Sending a cease-and-desist letter may not, on its own, be sufficient. In the regional court of appeal decision upheld by the decision of the 11th Civil Chamber of the Court of Cassation dated 5 March 2026, E. 2025/4311, K. 2026/1331, a cease-and-desist letter that was not followed by an action was disregarded and, in a case where the use had begun with permission, silence exceeding four and a half years was held sufficient for the purposes of the principle of good faith. For a person using a sign without registration, it would be advisable to retain dated documents showing the commencement and continuity of the use and not to delay registering the trade mark. Ultimately, silence before registration may not start the period running in an invalidity action, yet the same silence may, through the principle of good faith, come back to confront the claimant in an infringement action.

Legislation and Decisions CitedAtıf Yapılan Mevzuat ve Kararlar

IPC Article 7(1) · IPC Article 25(6) · IPC Article 155 · TCC Article 2 · Code of Civil Procedure Article 373(5) · Decree-Law No. 556 · 11th Civil Chamber of the Court of Cassation, 25 October 2022, E. 2021/3291, K. 2022/7375 · 11th Civil Chamber of the Court of Cassation, 3 April 2024, E. 2022/6764, K. 2024/2755 · 44th Civil Chamber of the Istanbul Regional Court of Appeal, 19 December 2024 · 11th Civil Chamber of the Court of Cassation, 19 March 2025, E. 2024/3476, K. 2025/1973 · 11th Civil Chamber of the Court of Cassation, 24 March 2025, E. 2024/3651, K. 2025/2081 · 11th Civil Chamber of the Court of Cassation, 24 September 2025, E. 2025/840, K. 2025/5647 · General Assembly of Civil Chambers of the Court of Cassation, 10 December 2025, E. 2024/376, K. 2025/798 · 11th Civil Chamber of the Court of Cassation, 5 March 2026, E. 2025/4311, K. 2026/1331 · 11th Civil Chamber of the Court of Cassation, 30 March 2026, E. 2025/4864, K. 2026/1820 · 11th Civil Chamber of the Court of Cassation, 4 June 2026, E. 2026/3054, K. 2026/3267

This article has been prepared for general information purposes only and does not constitute legal advice. The court decisions referred to are based on the decision texts accessible as at the date of publication; findings recorded in decision summaries are those of the relevant courts. This article does not create an attorney-client relationship and contains no undertaking as to its updating. 5 October 2026.

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