In T 117/86 (OJ 1989, 401) the appellants had produced, together with their statement of grounds, two new documents and an affidavit in support of the contention that the opposed patent lacked an inventive step. The board concluded that the fact that new documents were presented after the nine-month period for filing opposition could itself give rise to additional expenditure for the other party, and that the costs should be apportioned differently for reasons of equity.

The board in T 416/87, expressly referring to T 117/86, regarded it as an abuse of the opposition procedure that the appellant had in its statement of grounds of appeal relied exclusively on three new documents and had even raised for the first time the issue of novelty on the basis of a document already discussed in the patent in suit. By introducing arguments and documents which bore little relation to the content of those filed in the original opposition, the appellant had produced virtually a new opposition at the appeal stage. This could not, by definition, be the purpose of an appeal. Although the respondent clearly envisaged requesting a decision on costs in the event of oral proceedings only, the abuse of procedure justified the apportionment of costs incurred during the taking of evidence.

The board in T 83/93 held that it was also an abuse of the appeal procedure to submit five new documents as evidence 40 months after the end of the opposition period (without giving reasons) and to revive an objection under Art. 100(c) EPC 1973 on the basis of new facts and evidence 51 months after the end of the opposition period.

In T 493/11 the respondent introduced important evidence at a late stage of the proceedings, namely only two months before the date of the scheduled oral proceedings, without cogent reasons for the delay and, in particular, without submitting all the necessary information. The board stressed that the responsibility for stating its complete case lay exclusively within the respondent's own sphere. As a consequence, any delay causing the incurring of additional costs by the other party remained within the respondent's sphere and liability and, in the case in hand, justified an apportionment of costs.

In T 867/92 (OJ 1995, 126) the claims had been amended during the opposition proceedings. Eighteen months after the claims had been amended the appellant (opponent) cited in the statement of grounds of appeal a new prior art document. The board held that the EPC does not impose a time limit for citing new prior art in response to an amendment of the claims. However, an opponent who cites new prior art with a considerable delay with no special reason justifying the delay runs the risk of having to bear the proprietor's costs incurred in attending oral proceedings which cannot bring the case to an end because of the new citation. However, as there was no suggestion that the appellant (opponent) wilfully abused the procedure in the case at issue, the board considered that it would be equitable to order the appellant to pay only half those costs.

In T 514/01 the board found that the late allegation of public prior use during the first oral proceedings before the opposition division had given rise to additional costs because second oral proceedings before the opposition division had been needed to investigate the alleged prior public use.

In T 416/00 the appellant (opponent) submitted a document which had been cited in the patent in suit and mentioned in the opposition proceedings but had never been discussed between the parties until the appeal proceedings, and had even been expressly excluded before the opposition division. The board found that the opponent's attempt to make surprising use of a document that it had disregarded in the oral opposition proceedings ran counter to the speedy conclusion of the proceedings before the two departments. Even if this was not a deliberate tactic on the opponent's part, the result was the same in terms of the principle of fairness governing proceedings. The respondent's request for a different apportionment of costs was granted.

In T 671/03 document D18 was first filed in the appeal proceedings and deemed to constitute an amendment to the appellant's submissions pursuant to Art. 10b RPBA 2003 (Art. 13 RPBA (2007)). If it had been filed within the opposition period, there would have been no need to discuss its admission during the oral proceedings in the appeal. The costs for preparing and attending the oral proceedings before the board, which mainly discussed the admission of D18, could have been avoided. For reasons of equity the board ordered a suitably modified apportionment of costs.

In T 1033/09 the oral proceedings had been adjourned following the admission of an auxiliary request submitted by the respondent during those proceedings. For the board, there was no doubt that this auxiliary request constituted an amendment to the respondent's case after it had filed its reply to the statement of the grounds of appeal, and so one within the meaning of Art. 13(1) RPBA (2007). The board therefore found it equitable to apportion the costs in the appellant's favour.

Similarly, in T 2165/08 of 6 March 2013 date: 2013-03-06 the appellant (patent proprietor) filed its auxiliary requests 1 to 3 one month before the oral proceedings and further supporting documents even closer to the oral proceedings. The board stated that it would always be unacceptable for a party to produce evidence without any explanation – unless conceivably its relevance was self-evident. But to produce evidence at the virtual end of the proceedings accompanied only by a statement that the explanation would be provided even later was not only discourteous but a clear, and apparently deliberate, attempt to frustrate the respondent's preparation for the oral proceedings. That was both an act prejudicing the efficient conduct of oral proceedings and an abuse of procedure, which merited an apportionment of costs.

The board in T 874/03 ruled that when late filing of facts and evidence necessitated remitting the case to the department of first instance, the costs of any oral proceedings in the appeal proceedings were normally to be borne by the party responsible for the late filing.

In T 2233/09 the board concluded that it would have been possible for the appellant to submit the evidence necessary to prove transfer of appellant status well ahead of the oral proceedings and that it was its conduct that had caused the adjourning of the oral proceedings. Therefore, for reasons of equity, the respondent's costs for the new oral proceedings had to be borne by the appellant.

In T 1763/12 the board admitted document O6A into the proceedings even though it was filed only three days before the scheduled date for the oral proceedings. The appellant (opponent) did not give any reason why document O6A had only been submitted at such a late stage of the proceedings and why it could not have filed this document earlier. The consequence was that the discussion at the oral proceedings before the board was limited to the issue of admittance of O6A without considering any substantive matter. This would have been avoided if the document had been filed earlier. The board held it to be equitable that the expenses incurred by the appellant (patent proprietor) in connection with the oral proceedings be borne by the appellant (opponent).

In T 2549/12 documents which the appellant had filed with its statement of grounds of appeal amounted to new submissions that opened up a new discussion and a fresh case that had not been dealt with in the first-instance decision. The board refused to admit the documents. On the apportionment of costs, the board held that, where an entirely new case was first made on appeal (here, through filing the new submissions) and there were no mitigating circumstances that might excuse its being made so late, opportunities to make it at first instance having been missed and no explanation or justification for that being provided, it was appropriate to order a different apportionment of costs within the meaning of Art. 104(1) EPC.