SONN Patentanwälte – IP Attorneys

EPO case law: No negative burden of proof in the statement of opposition

According to the rules on the burden of proof applicable under the EPC, each party has to present and prove the facts that are favourable to it – the principle of "negativa non sunt probanda" applies. Accordingly, the prior use of handing over an item to a buyer must be presented and proven by the opponent, and any binding of the recipient by a confidentiality agreement must be presented and proven by the patent proprietor. Although the patent proprietor’s submissions may lead to a secondary burden of proof for the opponent, this can only apply "ex nunc" and thus without any effect on the substantiation requirement in the notice of opposition according to R 76 (2) c) EPC (EPO BoA 16 October 2019, T 2037/18, No negative burden of proof in the notice of opposition).