EPO oppositions: A cost-effective alternative to litigation

EPO oppositions are vastly cheaper than invalidity proceedings in each national court. In approximately 50 percent of cases, an opponent achieves success in the form of complete revocation or significant limitation of the patent. Oppositions represent an important tool for dealing with any European patent of a competitor that might pose a threat to commercial activities in Europe.

A European patent, once granted, begins a process of validation in each contracting state designated upon filing. At the end of this process, the patent holder is left with a separate national patent in each country. As a result, any challenge to the validly of the granted patent in the courts must be made on a country-by-country basis. However, the opposition procedure at the EPO provides an opportunity to challenge validity centrally for all 36 designated states.

Approximately 5 percent of all European patents are opposed, although this varies depending on the particular area of technology to which the patent relates.

Time limit

The non-extendable period for filing an opposition and paying the official fee expires nine months after publication of the grant of the European patent.

Any natural or legal person may oppose the grant of a European patent, other than the patent holder. It is also possible for a so-called ‘man of straw’ to file an opposition in order to disguise the identity of the true opponent.

No special interest or standing is required on the part of an opponent.

Grounds for opposition

The opposition must identify which of the various grounds of opposition is being invoked and provide a written reasoned statement of the facts, evidence and arguments that are relied upon. An insufficiently substantiated opposition will be deemed inadmissible and cannot be supplemented later.

The only permissible grounds for opposition are: