UKIPO Invalidates OpenAI GPT Marks in ChainGPT Action

The UK Intellectual Property Office has upheld an invalidity challenge brought by ChainGPT LLC against OpenAI’s UK registrations for marks incorporating the term GPT. In decisions published on 3 September 2026, the hearing officer found that GPT describes a generative pre-trained transformer system used in artificial intelligence goods and services. The technical meaning would be understood by relevant specialists in the trade, rendering the term devoid of distinctive character for the goods and services concerned. The same reasoning led to a finding that the composite mark ChatGPT also lacked inherent distinctiveness, with insufficient evidence that it had acquired distinctive character through use in the United Kingdom. As a result, the invalidity applications against the GPT and ChatGPT marks succeeded. OpenAI’s remaining opposition grounds, based on other GPT-formative marks, were considered in light of this outcome. The rulings illustrate how descriptive terminology tied to emerging technology can face heightened scrutiny during post-registration challenges. Small-business owners should conduct thorough distinctiveness assessments before filing marks that incorporate technical acronyms or industry shorthand.