IP-Fälle und Artikel

T 1201/14: Article 87(1) EPC takes priority

This case emphasises the importance of ensuring that any transfers during the priority year are executed correctly and evidenced appropriately.

The priority year is often crucial to the success of a patent application as well as the invention(s) embodied within. Inventors will often use this time to formally disclose their technology in order to attract further funding, which can in turn be used to generate further supporting data. These data can be included in subsequent filings and can even lead to new embodiments and/or inventions.

In order for this to work, the priority claim from the subsequent filing(s) must be valid. Our recent article on the subject of “poisonous priorities” (see notes below) demonstrated how the contents of the filings can influence this validity. Equally important to a priority claim are the legal requirements. Getting either of these wrong can be irrevocably destructive for the subsequent applications.

The law

While the legal requirements derive from the Paris Convention, every jurisdiction has its own statutory implementation. The EPC 1973 provides for this under Articles 87 to 89 and in Rules 52 to 54 (largely unchanged in the EPC 2000 revision). Article 87(1) EPC states that:

Any person who has duly filed, in or for (a) any State party to the Paris Convention for the Protection of Industrial Property or (b) any Member of the World Trade Organization, an application for a patent, a utility model or a utility certificate, or his successor in title, shall enjoy, for the purpose of filing a European patent application in respect of the same invention, a right of priority during a period of twelve months from the date of filing of the first application.

From this, the two fundamental legal requirements are that the right of priority can (1) only be enjoyed by the same person, or successor in title, and (2) only be derived for the same invention.


Decision T1201/14 concerns specifically the former requirement; in this case, the board was required to decide on whether an assignment of priority right had been validly executed in respect of the first (priority) application.

During the opposition proceedings, the proprietor (Innovative Sonic Limited) alleged that two assignments had taken place for the priority application (a US provisional application): from the inventor to ASUSTeK, and from ASUSTeK to the proprietor. The validity of the priority claim was critical to the disputed patent (EP 1883190B) as ASUSTeK disclosed the invention in the intervening priority year.

The Opposition Division was satisfied of the first transfer (to ASUSTeK), but rejected the second transfer (to the proprietor from ASUSTeK) as invalid. In particular, the Opposition Division pointed out that the correct reading of Art. 87(1) EPC (“…for the purpose of filing…”) would mean that there has to be evidence of the right of priority being transferred prior to the convention filing; in this case, the proprietor was relying on a back-dated (nunc pro tunc) assignment under US law. The Opposition Division also rejected the arguments from other national laws as being inapplicable.

The decision

Applicability of National Laws

The board appeared willing to hear the numerous arguments presented by the proprietor from different national laws in order to verify the validity of the second assignment. In particular, the board accepted that the available jurisprudence before the EPO already relied on several different laws as basis for the formal requirements for registering a transfer:

  • the law of the country where the first application was filed (lex originis)
  • the law of the country where the later application was filed (lex loci protectionis);
  • the law of the country which is agreed upon in the relevant contract (lex loci contractus;
  • the law of the country where at least one of the parties to the transfer has its residence (lex domicilii).


In the present appeal, the proprietor had relied on at least US law (lex originis), German law (lex loci protectionis – as an EPC-contracting state), and Taiwanese Law (lex domicilii – for where ASUSTeK was based)

The US law argument was essentially that the validity must be tied to the validity of nunc pro tunc assignments under US law, rather than on any reading of the EPC.

The German and Taiwanese law arguments were similar, and essentially focussed on the existence of a “general policy” at ASUSTeK to transfer priority rights of priority filings to the proprietor. These national Laws were relevant primarily for the fact that neither required an assignment to be concluded by way of a formal written contract. The proprietor further argued that Taiwanese law also did not differentiate the right to an application and the right to priority.

There was a further argument for a “direct” transfer by virtue of the transfer of “all rights” for a separate application which claimed priority from the same priority document in the presently contested patent.


The board rejected all of the proprietor’s arguments.

With regard to the US law argument, the board re-emphasised that this simply did not meet the fundamental requirement, as stated in Art. 87(1) EPC, that the assignment must have concluded prior to filing the second (convention) application. The board further stated that this was not an issue that had been disputed in other decisions (including the well known Edwards Lifesciences AG decision in the High Court - [2009] EWHC 1304 (Pat)), and thus further did not see a need to refer this point to the Enlarged Board.

With regard to the German and Taiwanese Law arguments, the board held that the transfer was not sufficiently evidenced. In particular, the fact that this relied on internal documents where the proof would only lie in the possession of the proprietor, the standard of proof had to be “beyond reasonable doubt” rather than on the “balance of probabilities” (as is normally the case before the EPO for eg, prior use). The board further noted that there was evidence that certain filings had not followed the alleged “general policy”, and this further cast doubt on the validity of transfer.

The “direct transfer” argument failed because the assignment simply concerned a different application, rather than the priority application in question.

The board also noted, in relation to the Taiwanese law argument, that irrespective of the stance of a national law on whether or not a priority right is separable, a substantive requirement of the law according to the EPC was that there had to be a specific transfer of the priority right, which is independent of the right to the application. Thus, mere transfer of an “application” would not necessarily indicate the transfer of a priority right in that application.


The EPO neatly sidestepped the question of whether any particular national laws would take precedence over another if there was ever conflict between laws in determining the validity of a transfer. However, this case further emphasises the importance of ensuring that any transfers during the priority year are executed correctly and evidenced appropriately.


  1. Related article: “G 1/15 resolves question of poisonous priorities” by Alan Boyd, published 06 February 2017 concerning the issue of “poisonous priorities” where an applicant’s own priority application is used against a subsequent patent application: www.dyoung.com/knowledgebank/articles/g115-decision

Case details at a glance

Jurisdiction: European Patent Office
Decision level: Boards of Appeal
Parties: Innovative Sonic Limited (applicant) and Telefonaktiebolaget L-M Ericsson (opponent)
Date: 09 February 2017
Citation: T1201/14
Link to full decision: http://dycip.com/t120114