Legal framework
Under Article 99(1) EPC, any person may file an opposition within nine months of publication of the mention of grant, and the opposition is not deemed to have been filed until the opposition fee has been paid. Here, the mention of grant of EP-X was published on 6 December 2024, and the opposition fee was paid on 5 September 2025.
The contents of the notice of opposition are governed by Rule 76 EPC. The notice must include the patent opposed, the extent of opposition, the grounds, and an indication of the facts and evidence relied on. It is not a strict admissibility requirement that copies of all cited patent documents be filed within the opposition period, provided that the evidence is adequately identified and the opposition is sufficiently substantiated.
Statement a)
Statement a) is false.
The opposition is not inadmissible merely because copies of D1 and D2 were filed after expiry of the opposition period.
The notice of opposition filed on 5 September 2025 explained why the claimed subject-matter lacked inventive step in view of D1 and D2, and D1 and D2 were explicitly identified. Under Rule 76(2)(c) EPC, what is required for admissibility is an indication of the facts and evidence supporting the opposition grounds. The EPO Guidelines confirm that the notice must establish the legal and factual framework of the case, but it is not necessary that a final decision can be taken without further investigation.
Under Rule 83 EPC, documents referred to by a party should be filed with the notice of opposition or the written submissions. If they are not enclosed or later filed in due time upon invitation, the EPO may decide not to take arguments based on them into account. This is not the same as automatic inadmissibility of the opposition.
Statement b)
Statement b) is true.
The opposition period is nine months from publication of the mention of grant under Article 99(1) EPC. The mention of grant was published on 6 December 2024, so the nine-month period expired on 6 September 2025 under Rule 131(4) EPC.
However, 6 September 2025 was a Saturday. Under Rule 134(1) EPC, if a period expires on a day on which the EPO filing offices are not open for receipt of documents, the period is extended to the next day on which they are open and mail is delivered. The next working day was Monday 8 September 2025.
Therefore, the notice of opposition could have been filed at the latest on 8 September 2025.
Statement c)
Statement c) is true.
The notice of opposition was written in Portuguese. A Portuguese citizen resident in Portugal may use Portuguese under Article 14(4) EPC, because Portugal is an EPC contracting state and Portuguese is an official language of that state but not an official language of the EPO. A translation into an EPO official language must then be filed in accordance with the Implementing Regulations.
Under Rule 6(2) EPC, a translation under Article 14(4) EPC must be filed within one month of filing the document. For a notice of opposition, the translation may instead be filed within the opposition period if that period expires later. Here, the notice was filed on 5 September 2025, so the one-month period was still open on 25 September 2025.
The English translation was therefore filed within the prescribed time limit.
Statement d)
Statement d) is false.
The Portuguese citizen did not have to appoint a professional representative merely in order to file the opposition.
Under Article 133(1) EPC, no person is compelled to be represented by a professional representative, subject to the exception in Article 133(2) EPC. That exception applies to persons who do not have their residence or principal place of business in an EPC contracting state. Since the opponent is resident in Portugal, an EPC contracting state, Article 133(2) EPC does not require professional representation.
Thus, the opposition is not invalid for lack of a professional representative.
Exam tip
For opposition formalities, separate three issues:
First, the notice and fee must be filed within the nine-month opposition period.
Second, if the opposition is filed in an admissible non-EPO language under Article 14(4) EPC, check the separate translation period under Rule 6(2) EPC.
Third, cited documents should be filed, but failure to file copies together with the notice is not automatically fatal if the documents are clearly identified and the opposition is sufficiently substantiated.
Legal Disclaimer
The information provided in this post is for general informational purposes only and does not constitute legal advice. This content should not be used as a substitute for professional legal advice tailored to your specific circumstances. For advice related to any specific legal matters, you should consult a qualified attorney.