An opposition is a formal request for revocation of a patent, which can be filed by a third party within nine months of patent’s grant by the European Patent Office.
Importantly, oppositions can be filed anonymously. As in, the identity of the party directing the opposition is not visible to the public. This is often done by having the opposition filed in the name of the representing attorney, or their firm, or in the name of a separate legal entity – sometimes a vehicle company created specifically for this purpose (e.g. Strawman Ltd).
We analysed the most active opponents at the EPO in 2024, based on the number of oppositions filed by each individual entity. The results are visualised in the chart below.
Topping the list is Henkel, the global manufacturing company, which filed 53 oppositions last year. Notably, their primary target was Unilever.
Given that most oppositions are filed in the healthcare sector, it’s no surprise to see two major generics companies – Teva and Generics (UK) Ltd – also among the most active opponents (straw coloured in the chart). Clicking on their names in the visualisation reveals the wide range of patents they challenged, across diverse technologies and innovator companies.
At the other end of the transparency spectrum, the entities covering the broadest range of technical fields are, unsurprisingly, two anonymous opponent vehicles: Strawman Limited, and a European patent attorney firm (pink in the chart).
There are many strategic reasons why a company might choose to file an opposition without revealing their identity. For example:
- They may wish to avoid publicly signalling interest in a particular technical field.
- They might prefer not to risk complicating possible future licensing negotiations with the patent holder.
The Mewburn Ellis company for filing anonymous oppositions is Margaret Dixon Limited, named after the first woman to practice as a UK patent agent. Margaret Dixon took up the profession 1926, at Mewburn Ellis.
A final note: we’ve deliberately used the term visible opponents in the title of this piece. It’s entirely possible that another company filed a much larger number of oppositions in 2024 but divided these up to be filed in the names of multiple anonymous vehicles. In that case, the true most active opponent of the year might be hiding in plain sight.
At Mewburn Ellis, we’re representing clients on both sides of the table, defending and opposing patents across a range of sectors. If you're considering filing an opposition, or if your patent has been opposed, our specialist teams in Life Sciences, Chemistry, and Engineering & ICT are here to help.
