1. Principle that each party must bear its own costs

Under Art. 104(1) EPC, each party to opposition proceedings must, as a rule, bear the costs it has incurred. However, the opposition division or board of appeal may, for reasons of equity, order a different apportionment of the costs. At the appeal stage Art. 16(1) RPBA also applies, allowing the board, subject to Art. 104(1) EPC, to order a different apportionment. It lists typical cases where costs arise as a result of: (a) amendments to a party's appeal case pursuant to Art. 13 RPBA; (b) extension of a period; (c) acts or omissions prejudicing the timely and efficient conduct of oral proceedings; (d) failure to comply with a direction of the board; or (e) abuse of procedure.

In T 133/06 the board added that Art. 104 EPC belonged to the procedural provisions and so was subject to the general principle of law that a new procedural law was immediately applicable but had no retrospective effect unless otherwise provided. Hence when deciding whether the new Art. 104 EPC (i.e. Art. 104 EPC 2000) is applicable in appeal proceedings initiated under EPC 1973, the board must take into consideration not only the fact that, according to the transitional provisions (see decision of the Administrative Council of 28 June 2001, OJ SE 1/2007, 197), the new Art. 104 EPC is applicable to granted patents, but also the date of the event which gives rise to the application of this article. This is the only way to give the new procedural provision an immediate application without giving it a retrospective effect.

In T 66/18 the board held that Art. 104(1) EPC applied only to adversarial proceedings such as opposition proceedings. An alleged abuse during examination, i.e. before and not during opposition proceedings, did not fall within the scope of Art. 104(1) EPC. It further observed that the possibility of apportioning costs was treated in the case law not as a means of imposing a fine but rather as a way of granting at least partial compensation for conduct during opposition proceedings that fell short of the due level of care.