2.1. General

Pursuant to Art. 87(1) EPC, a right of priority, that is, the right to claim priority for a European patent application from the filing date of an eligible "first application" or "previous application" originates in the applicant of a first application (T 205/14, cited by the Enlarged Board in G 1/22 and G 2/22, OJ 2024, A50, point 83 of the Reasons). The right of priority may, in accordance with Art. 87(1) EPC, also be invoked by the "successor in title" of the person who filed the first application. By reference to the "successor in title", it is recognised that the right of priority, being a legal right, may be transferred from the original applicant to a third person (see e.g. T 62/05, T 5/05, T 382/07, T 1933/12 and T 517/14).

According to the board in T 205/14, it is generally accepted that the right of priority is transferable independently of the corresponding first application and may be transferred to a third person for one or more countries only (T 62/05). It is an independent right until it is invoked for one or more later applications to which it becomes an accessory, and it has to be distinguished from the right to the patent deriving either from substantive law or from the status of being the applicant of the first application (T 205/14, with further references; see also T 969/14; and T 1201/14, with further references).

The board in T 969/14 held, with reference to Enlarged Board decision G 1/15 ("Partial priority", OJ 2017, A82), that once it is acknowledged that partial priority rights exist they must also be transferable separately. This, however, has consequences for the remaining priority right, because the assignor is left with a limited right. On partial and multiple priorities, see also in this chapter II.D.6.