According to T 9/00 (OJ 2002, 275), the repeated filing of an opposition by the same person could be objected to for lack of legitimate interest. A (legal) person who filed two different notices of opposition against the same patent acquired party status as an opponent only once, even if both notices complied with the requirements of Art. 99(1) EPC and R. 55 EPC 1973 (R. 76 EPC). Both oppositions in question gave lack of novelty and lack of inventive step as grounds. Since the later opposition did not entail any change in the legal situation in the opposition proceedings compared to the earlier one, the board dismissed it as inadmissible for lack of a general legitimate interest. Nor could such an interest be inferred from the fact that the later opposition was assigned to a different part of the company and only that part of the company had been transferred to a third party. The status of opponent could pass to a third party only if both parts or the entire company were transferred to it.

In T 774/05, a notice of opposition was filed on one day, enclosing a cheque for the opposition fee but no reasoned statement. On the following day further documents were filed which included patent documents and a reasoned statement referring to a notice of opposition. According to the board, the opponent's intention was to maintain a single opposition, as evidenced by the statement in the faxes that the cheque for the opposition fee presented the day before should be used for the opposition. The only indication of separate oppositions was the fact that both the document filed initially and the faxes of the following day each stated that they were an opposition. This was not an indication, however, of an intention on the part of the opponent to file two oppositions but rather an indication of their content. Taking all these documents together, the board considered that the opponent had filed only one opposition, for which the requirements for a valid filing were completed within the opposition period. The opposition was therefore admissible.

In T 966/02, the same opponent had filed two oppositions, the second of which cited document D1, on which the opposition division based its decision. The main issue was whether the opposition division had been competent to use the document cited in the second opposition. The board stated that the first opposition had been filed in due form and time and was therefore admissible. Hence there was no need to decide whether the second opposition was admissible, since the department of first instance was, in any event, competent to take account of both document D1 and any other relevant material of its own motion (Art. 114 (1) EPC).