1.6 Applicant's entitlement to claim priority 

The applicant claiming the priority of an earlier application must be the applicant of the latter or the successor in title of the priority right. The question of whether the applicant is actually entitled to claim the priority of an earlier application is not examined during the international phase.

In proceedings before the EPO as designated or elected Office, the transfer of the priority right must be assessed under the EPC, regardless of any national laws. The EPC does not set out any formal requirements for the transfer of the priority right (see G 1/22 and G 2/22). For details on the procedure before the EPO as designated or elected Office, see GL/EPO A‑III, 6.1.

Proof of entitlement on the international filing date must be submitted in the proceedings before the EPO (only) if the validity of the priority right claimed becomes relevant. However, for a successor in title to enjoy a priority right in proceedings before the EPO, the earlier application or the priority right must have been transferred before the filing date of the international application (Box No. VIII (iii) PCT request form) and the transfer must be valid under the applicable national provisions. Any deficiencies cannot be remedied after that, and in particular not in the European phase.

Applicants claiming the priority of an earlier application and planning to enter the European phase are therefore strongly advised to ensure that, as at the international filing date, all applicants who filed the earlier application are either mentioned as applicants in the international application or have validly transferred their rights to the applicant, or one of the applicants, in the international application. For example:

–The earlier application from which priority is claimed names X as applicant. The international application names company A as applicant. For A to enjoy a priority right in proceedings before the EPO as designated Office, X must have validly transferred the earlier application or the priority right to A before the filing date of the international application.

Where joint applicants file an international application and claim the priority of an earlier application, it is sufficient that one of them is the applicant who filed the earlier application or that applicant's successor in title. Since the international application has been filed jointly – which shows that the applicant who filed the earlier application consents – there is no need for a special transfer of priority right to the other (additional) applicant(s). For example:

–The earlier application from which priority is claimed names X as applicant. The international application names X and company A as applicants. A transfer of the priority right from X to A is not required in order for A to enjoy a priority right in the proceedings before the EPO as designated Office.

–The earlier application from which priority is claimed names X as applicant. The international application names companies A and B as applicants. In order for both A and B to enjoy a priority right in the proceedings before the EPO as designated Office, X must have validly transferred the earlier application or the priority right to either A or B before the filing date of the international application. A transfer to both A and B is not required but would also fulfil the requirements for claiming priority in the European phase.

If the earlier application was filed by several applicants, all of them must be applicants in the international application or have transferred their rights to the applicant, or one of the applicants, of the international application. It is not sufficient if only one of several applicants filing the earlier application is named as applicant in the international application. For example:

–The earlier application from which priority is claimed names X, Y and Z as applicants. The international application names company A as applicant. X, Y and Z have not transferred their rights but are all named – together with company A – as applicants in the PCT request form (Box No. II and III). In such a situation, no further action is required in order for A to enjoy a priority right in the proceedings before the EPO as designated Office.

–The earlier application from which priority is claimed names X, Y and Z as applicants. The international application names company A and X as applicants. In order for both A and X to enjoy a priority right in the proceedings before the EPO as designated Office, Y and Z must have validly transferred their rights to the earlier application to either A or X before the filing date of the international application.