The landscape of European patents has been fundamentally reshaped by the arrival of the Unified Patent Court (UPC) in June 2023. This has profound implications for how businesses manage and mitigate the risk posed by competitors' patents. A look at the number of patents opposed at the European Patent Office (EPO) in recent years suggests that, even with the new option of central revocation at the UPC, the EPO opposition procedure remains a crucial strategic tool.
A tale of numbers: Opposition trends before and after the UPC
The number of oppositions filed at the EPO provides a useful barometer of the perceived value of the opposition procedure as a strategic tool for challenging competitors’ patents.
From a pre-pandemic level of more than 3000 European patents opposed annually, there was a steady decline in the post-pandemic period to a low point in 2022. This dip from 2020 until 2023 can be attributed to several factors. It follows, to a large extent, the number of grants in the previous year, running at a fraction of around 1.5‑2.5% of all patents granted over the time period. Additionally, the economic shock of the pandemic was followed by a period of significant macroeconomic uncertainty, with rising inflation and geopolitical instability leading many companies to tighten budgets and focus on core activities, deferring discretionary legal spending. This climate of caution likely contributed to the slide in grants and opposition filings.
This has been followed by a significant recovery in the number of granted patents and opposition filings in 2023 and 2024:
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2023: 2510 opposed patents (2.4% of 104,609 granted patents)
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2024: 2300 opposed patents (2.1% of 109,524 granted patents)
The rebound in opposition filings in 2023 and into 2024 is particularly noteworthy as it coincides with the first full year of the UPC's operation. While the rebound reflects an increase in granted patents in total, the availability of central revocation actions under the UPC seems not to have significantly diminished the number of patents that are opposed.
Another set of numbers confirms the picture that EPO oppositions will remain highly relevant in the new UPC world. Of the 218 patents that are or have been subject to UPC revocation actions, about half have been opposed. Out of those, 55 of the patents involved have been opposed since the UPC opened its door and, indeed, about half of those, 23 patents, have been opposed after the revocation action was started. This clearly shows that, far from displacing oppositions as the validity forum of choice, the use of parallel UPC and EPO oppositions proceedings can be a strategically valuable option in a comprehensive patent challenge strategy.
EPO opposition versus UPC revocation action – why the continued interest in EPO oppositions?
At first glance, one might expect the UPC – which offers a mechanism to centrally revoke a patent in all of the participating member states – to diminish the appeal of the EPO's time-limited opposition procedure. Why rush to file an opposition within nine months of grant when you can (at least in principle) file a revocation action at the UPC at any time? The reality is more nuanced, and several compelling strategic factors make the EPO opposition an enduringly attractive, and generally complementary, option.
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Pan-EPC revocation via the EPO: Perhaps the most important reason oppositions remain of interest is the difference in jurisdictional reach between the UPC and the EPO. The UPC can revoke the patent in just the participating member states (18 states at the time of writing). In contrast, an EPO opposition is the only way to revoke a patent in all EPC member states e.g. including the UK, Spain, Switzerland, Ireland, Turkey etc.
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Cost-effectiveness: Another important factor is the stark cost differences between the procedures. Currently, the official fee for filing an opposition at the EPO is €880, while initiating a revocation action before the UPC requires payment of an official fee of €20,000. Representation costs for first instance EPO opposition proceedings will typically be less than those for a UPC revocation action, likely by a factor of 5 or more. A further difference lies in cost recovery. Unlike the EPO, where each party typically bears its own costs, the UPC operates on a "loser pays" principle – introducing a significant financial risk that is largely absent from the EPO opposition process.
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A well-established and trusted procedure: The EPO opposition procedure is well established. It has been refined over decades, and the technical and legal members of the Opposition Divisions and Boards of Appeal have deep expertise. This relative predictability is invaluable when making strategic decisions, and contrasts with the UPC that has yet to develop an established body of case law.
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Anonymity: EPO oppositions can be filed by any third party, allowing the true interested party to use a "straw man" and remain anonymous. This is a significant strategic advantage, enabling a company to challenge a competitor's patent without signalling its commercial interests or inviting retaliation. A UPC revocation action must be filed in the name of the interested party.
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Patentee control over UPC jurisdiction: During the 7-year transitional period, the UPC has jurisdiction over all unitary patents (UPs), as well as classical European patents that haven’t been “opted out” of the UPC system. So, while in principle it’s possible to bring a UPC revocation action against a classical EP, in practice the patentee controls whether the UPC can be used as the forum. For now, would-be challengers may have limited influence on the forum for central revocation, but this balance is set to shift as UPs – which cannot be opted out – gain popularity and the transitional period (along with the opt-out mechanism) comes to an end. In the meantime, EPO oppositions may be the only central revocation route available.
Of course, in some circumstances a UPC revocation action may be available and the preferable option. Once the nine‑month EPO opposition window has closed, a revocation action before the UPC offers the only route to centrally revoke a patent across participating member states. Speed is a key advantage: the UPC aims to issue decisions within 12 months, meaning a revocation action filed at grant could lead to a decision just months after the opposition period ends. A new UPC revocation action may also be the preferred route to consider new prior art or evidence of prior use that surfaces late in EPO opposition or appeal proceedings, where such material – in contrast to the EPO proceedings – may be considered without admissibility challenges. Moreover, the UPC allows reliance on national prior rights – which are excluded from EPO oppositions – offering a powerful strategic advantage when such documents exist. Together, these factors make the UPC a valuable complementary tool for challenging patent validity in Europe.
In the absence of these specific circumstances, however, EPO oppositions will likely continue to be the preferred patent revocation route, thanks to their broader jurisdictional reach and significantly lower costs.
From reactive to proactive: The imperative of an opposition strategy
There are many strategic reasons for filing EPO oppositions, whether proactively to clear a path for a new product or reactively if a storm is brewing with a competitor. However, the immovable nine-month opposition deadline following a patent's grant means that a purely reactive stance is rarely viable. By the time a competitor's patent becomes an imminent threat, the opposition window has often long since closed.
Effective use of the opposition procedure requires a proactive approach. This involves systematically monitoring the grant of potentially problematic patents from competitors and implementing a defined process for handling the results. This process should allow for a swift but thorough assessment of the risk posed by a newly granted patent, enabling a considered decision on whether an opposition is strategically and commercially indicated. To ensure the nine-month opposition window isn’t missed, frequent monitoring and the timely review of the results are crucial ingredients in an effective opposition strategy.
In the high-stakes UPC era – with the possibility of pan-European injunctive relief – leaving a potentially invalid, business-critical patent unchallenged is a risk that needs to be considered carefully.
Whether you're developing a new opposition strategy, refining an existing one, or evaluating the relative merits of central revocation via the UPC and EPO, now is the time to engage with the evolving landscape. To explore how these tools can support your commercial and IP objectives, please reach out to Alexander Korenberg, Susan Hancock, or your usual Kilburn & Strode contact.