An Invalidity Action Against Your Trademark: An SMK Art. 25 Defence Guide

Owning a registered trademark does not mean that mark is beyond challenge. Someone else can bring an invalidity action arguing that your mark should never have been registered. Before you panic on receiving such a notice, here is what you should know: SMK 6769 grants the defendant trademark owner concrete defensive tools. This article summarises the key defences in an invalidity action.

What is invalidity, and where is it heard?

Invalidity is the retroactive removal of a trademark from the register by court decision. The mark takes effect as if it had never been registered (SMK art. 27). With SMK 6769 in 2017, invalidity actions are heard by the Intellectual and Industrial Property Civil Courts — not at TÜRKPATENT. This means the process is a litigation, so evidence and defence are decisive.

Grounds for invalidity fall into two groups:

• Absolute grounds (art. 5): lack of distinctiveness, descriptiveness, contrariety to public order, etc.
• Relative grounds (art. 6): likelihood of confusion with an earlier mark or right, prior use, etc.

Defence 1 — Five-year acquiescence

One of the strongest defences is the loss of right through acquiescence (art. 25/6). If the earlier-mark owner knew of your mark and tolerated your use for five years, they can, as a rule, no longer seek invalidity. The exception: proof that your application was made in bad faith.

Practical consequence: if you have used your mark openly for a long time and the claimant was aware of it, gathering the record of that elapsed time (invoices, advertisements, packaging) forms the basis of the defence.

Defence 2 — The claimant's non-use defence

In an invalidity action, if the claimant relies on an earlier mark, they must prove genuine use of that mark. SMK art. 25/7, by reference to art. 19/2, gives the defendant the right to request proof of use: if the claimant cannot prove genuine use of the mark in the last five years for the goods/services at issue, an invalidity claim based on that mark fails.

This is decisive in many files: an action brought on a mark that exists on paper but is not actually used is weakened by a request for proof of use.

Defence 3 — Rebutting the ground itself

In addition to acquiescence and the non-use defence, the ground for invalidity must be rebutted on the merits:

• For relative grounds: showing there is no likelihood of confusion (different goods/services, different overall impression).
• For absolute grounds: showing the mark is distinctive or has acquired distinctiveness through use.

The process — step by step

1. Action and notice: The invalidity action is filed and served on the defendant.
2. Statement of defence: A timely response is filed; the acquiescence and non-use defences are raised here.
3. Evidence: Evidence of use (invoices, advertisements, sales records) and proof of dates are submitted.
4. Expert examination: An expert report on matters such as likelihood of confusion and intensity of use.
5. Decision: The court's decision; if unfavourable, appeal and then the Court of Cassation route remain open.

The most common mistake

The most common mistake of defendant trademark owners is to miss the response deadline or gather evidence of use too late. If the acquiescence and non-use defences are not raised in time and correctly, a strong defence can be lost. So you must start compiling evidence as soon as you receive the notice.

We covered the opposition-stage process earlier in the trademark opposition process; invalidity is the later, court stage. We run the defence in an invalidity action at Asil Patent — under the agency of Salih Aksebzeci — from evidence preparation to case management. For details, see the Trademark Opposition & Defence service page.

Sources

1. SMK 6769 art. 25 (invalidity), art. 27 (effect)
2. SMK 6769 art. 25/6 (acquiescence), arts. 25/7 and 19/2 (proof of use)
3. Court of Cassation 11th Civil Chamber case law

---

Author: Salih Aksebzeci · TÜRKPATENT Agent Registry No. 188 · Published: 2026-06-23