In T 711/99 (OJ 2004, 550) the board emphasised that the exception stated in G 4/88 to the general principle that an opposition was not freely transferable should be construed narrowly. In G 4/88 the Enlarged Board had considered a situation where the commercial vehicles department, which was subsequently sold, was without legal personality. The company which filed the opposition was the only one entitled to do so. In T 711/99, by contrast, the issue was whether the opponent parent company should be recognised, in the event of the sale of a subsidiary that has always been entitled itself to file oppositions, as having the right to transfer its opponent status. The board denied this and held that the opponent status could only be transferred together with the assignment of part of the commercial activity of an opponent with sole legal authority where the transferred company division or department did not have that status and therefore lacked legal personality. It added that the notion of legitimate interest in the proceedings, which was irrelevant for the admissibility of an opposition at the time of its filing, likewise had no bearing on the opponent's status at any subsequent stage.

In T 1091/02 date: 2004-07-23 (OJ 2005, 14) the board challenged the case law subsequent to G 4/88 which required, for a transfer of opponent status outside universal succession, a transfer of the relevant business or part of it (T 659/92, T 670/95, T 298/97, T 711/99). It referred to the Enlarged Board questions which included the following: Can a legal person who was a wholly owned subsidiary of the opponent when the opposition was filed and who carries on the business to which the opposed patent relates acquire opponent status if all its shares are assigned by the opponent to another company and if the persons involved in the transaction agree to the transfer of the opposition?

In G 2/04 (OJ 2005, 549) the Enlarged Board decided that there was no convincing reason, in particular not any overriding interest of the parties or the public, to extend the application of the rationale of G 4/88 to the case where a subsidiary company was sold in whose interest the opposition had been filed by the parent company. Thus, a legal person who was a subsidiary of the opponent at the time when the opposition was filed and who carries on the business to which the opposed patent relates cannot acquire the status as opponent if all its shares are assigned to another company. In its reasoning, the Enlarged Board emphasised that in G 4/88 the Enlarged Board was faced with a situation in which, for legal reasons, it was not possible from the outset to attribute the procedural status of opponent to the business in whose interest the opposition was filed, whereas the Enlarged Board in G 2/04 was concerned with the situation in which the holding company did not want to attribute the procedural status of opponent to the entity in whose interest the opposition was filed. The opponent could easily have made provision for a future eventuality that its subsidiary should take over the responsibility for the opposition. If the holding company and subsidiary had filed the opposition as common opponents, the holding company could have withdrawn from the opposition at any time, leaving the subsidiary as the sole opponent. The Enlarged Board noted that a liberal admission of transfers could often result in the need to examine contested questions of fact or difficult questions of company law. This would broaden the possible procedural battle-fields for the parties and give rise to complications and delays in opposition proceedings.