BlogCopyrightTrade Marks
September 6, 2026

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4 min read

Implications of copyleft licence on trade mark applications for device and composite marks.

Most software incorporates open source code of some sort. This reduces time and cost of development, as the software developer doesn’t need to re-invent the wheel to achieve each functionality. The developer can just use third party code known to achieve the desired functionality.

The open source code is used by the software developer under licence. If the open source software is licenced under a copyleft licence, then all derivative works must be licenced under the same terms. That means that the sequence of code within which the open source software is incorporated, all becomes open source itself.

This has huge implications for a business that had plans to licence its software under a SaaS licence agreement, for a licence fee. Its entire business model might be thwarted by the requirement that its software is actually licenced for no fee, as a piece of open source software itself.

For this reason, one of the most important aspects of negotiating and drafting a contract for service, assignment, or licence of software is the provisions around use of open source code. This is something copyright lawyers have been cognisant of for decades. But it was never of much relevance to trade marks attorneys.

Open source software had no impact on trade marks…until AI.

Most large language models are trained on GPL code (open source code with copyleft licence terms). This makes the LLMs derivative works, governed by the same copyleft terms. And works created by those LLMs? They’re derivative works too, governed by copyleft terms. This means, all the AI outputs are potentially open source, free for all to use, without restriction, including logos.

When an applicant uses an LLM to create a logo, there is a chance that logo is itself open source. Applying to register an AI generated logo as a trade mark could be a restriction on third party use of the logo in a way that breaches the terms of the open source licence. The trade mark application, which would put the applicant in breach, may be challenged on the basis that it is, for example: made in bad faith, or contrary to law.

So, the use of open source software is now highly relevant to trade marks attorneys. All prudent attorneys should now ask, prior to filing, was a logo wholly or partly created by AI and, if so, what were the terms of the LLM that was used (and of the code that it was trained on). Even if the terms don’t make the logo open source yet, Yale researchers have recommended that all output generated by AI be governed by copyleft terms in future (See: Yale researchers propose ‘copyleft’ rules for generative AI | Yale News). If this happens, it will reinforce the importance of human creativity as the fundamental underpinning of intellectual property rights, specifically copyright and trade marks in so far as they comprise copyright works (including device and composite trade marks).

If you want to file an Australian, New Zealand or international trade mark application and want to do it properly, through attorneys that are conscientious and diligent, thinking through all the issues and the implications (rather than just slapping something together that may or may not even be valid or enforceable when the time comes to rely on it), then come to Tarr Law. We would love to help you.

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