Legal framework
Under Article 87(1) EPC, a person who has duly filed an earlier application, or that person’s successor in title, enjoys a right of priority for filing a European patent application in respect of the same invention during a period of twelve months from the filing date of the first application.
The calculation of EPC periods is governed by Rule 131 EPC. For a period expressed in months, the period expires in the relevant later month on the day having the same number as the day of the relevant event; if that later month has no such day, the period expires on the last day of that month.
The declaration of priority is governed by Rule 52 EPC. It should preferably be made on filing the European patent application, but it may still be made within sixteen months from the earliest priority date claimed.
Finally, under Rule 134(1) EPC, if a period expires on a day on which an EPO filing office is not open for receipt of documents, the period is extended to the first following day on which all filing offices are open and mail is delivered.
Statement a)
Statement a) is false.
EP-I was filed on 29 February 2024. The priority period under Article 87(1) EPC is twelve months. Applying Rule 131(4) EPC, the corresponding month is February 2025. Since February 2025 has no 29th day, the period expires on the last day of that month, namely 28 February 2025.
Therefore, the priority period does not expire on 3 March 2025.
Statement b)
Statement b) is true.
The priority declaration for EP-II may still be made within sixteen months from the earliest priority date claimed, according to Rule 52(2) EPC. Starting from 29 February 2024, the 16-month period expires on 29 June 2025 under Rule 131(4) EPC.
However, 29 June 2025 was a Sunday. Since the EPO filing offices are not open for receipt of documents on such a day, Rule 134(1) EPC extends the period to the next working day, namely Monday 30 June 2025.
Thus, the statement is correct.
Statement c)
Statement c) is true.
Article 87(1) EPC expressly requires the later European patent application to be filed “in respect of the same invention” as the earlier application.
Accordingly, EP-II can validly claim priority from EP-I only for subject-matter that relates to the same invention as disclosed in EP-I.
Statement d)
Statement d) is false.
Article 87(1) EPC does not limit the right of priority to the original applicant of EP-I. It also extends the right to the applicant’s successor in title.
The Enlarged Board of Appeal has also confirmed that the EPO is competent to assess entitlement to priority, and that there is a rebuttable presumption that the applicant claiming priority in accordance with Article 88(1) EPC and the Implementing Regulations is entitled to do so. This presumption can also apply where the priority applicant and the later applicant are not identical.
Therefore, Company X does not necessarily need to have been the applicant of EP-I at the filing date of EP-I. It may validly claim priority if it is the successor in title or otherwise validly entitled to rely on the priority right.
Exam tip
When the priority date is 29 February, always check whether the corresponding later month has a 29th day.
For a 12-month priority period, 29 February 2024 + 12 months = 28 February 2025.
For the 16-month priority-declaration period, 29 February 2024 + 16 months = 29 June 2025, then check whether Rule 134 EPC extends the deadline.
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.