Art. 72 EPC provides that an assignment of a European patent application must be made in writing and requires the signatures of the parties to the contract. Under R. 22 EPC, a transfer of a European patent application is recorded in the Register of European Patents at the request of an interested party and on production of documents satisfying the EPO that the transfer has taken place. This is in line with the PCT system (R. 92bis.1 PCT).

In J 12/00 the board summarised the preconditions for registering a transfer of a European patent application (now enshrined in R. 22 EPC) as follows: (i) a request of an interested party; (ii) the production of documents satisfying the EPO that the transfer has taken place; and (iii) the payment of an administrative fee. Documents relating merely to the obligation to transfer the right, but not to the transfer itself, were not sufficient to satisfy the EPO. Nor, according to the board, was it enough to cite registrations in different countries on the basis of documents other than assignment documents (similarly J 4/10).

In T 128/10 the board held that the three requirements under R. 22 EPC in conjunction with R. 85 EPC, as formulated in J 12/00, did not need to be fulfilled at the same time. If they were met on different dates, the transfer would only have effect vis-à-vis the EPO at the date on which all the requirements mentioned above were fulfilled.

In J 38/92 and J 39/92 the Legal Board of Appeal ruled that a transfer could only be recorded in the European Patent Register on the basis of an official document in accordance with R. 20(1) EPC 1973 if that document directly verified the transfer (similarly J 4/10). It did not suffice if a judgment was submitted which mentioned another document from which it was possible to verify the transfer.

In appeal proceedings, assessing whether there are documents satisfying the EPO that a transfer has taken place in accordance with R. 20(1) and (3) EPC 1973 and recording the transfer in the Register is a matter for the department of first instance responsible for making the entry in the Register. Accordingly, in appeal proceedings, substitution of another party for the original applicant is possible only once the relevant department of first instance has made the entry or where there is clear-cut evidence of a transfer (J 26/95, OJ 1999, 668; see also T 976/97, T 1751/07). In T 393/15 the board held that evidence of a transfer could not be regarded as clear-cut if the person carrying out the transfer had not been clearly authorised to do so.

A transfer can be recorded in the European Patent Register even after deemed withdrawal of a patent application, if it is still possible that restitutio is available and the successor in title has taken, together with his request for registering the transfer, procedural steps suitable for restoring the application (J 10/93, OJ 1997, 91).

In J 17/12 the board held that the transfer of a European patent application may not be recorded in the European Patent Register at a time when proceedings for the grant of the application are stayed under R. 14(1) EPC. There is nothing to stop the filing, during the suspension of grant proceedings, of a request to transfer the application, but no action will be taken on the request during the suspension. While the fact of the transfer may not be apparent from the register, it will be apparent from an inspection of the public file, as will the decision to stay the grant proceedings itself.

In J 17/14 the board decided that the reversal of a completed transfer in the Register was not necessarily justified simply because doubts subsequently arose as to whether the claimed succession had been satisfactorily proven. There were cases where it might be more appropriate to stay the grant or opposition proceedings in favour of the party originally registered.