Articles 87 to 89 EPC: Priority right, claiming priority and effect of priority right

Text of Articles 87 to 89 EPC

In plain English

Article 87 gives a 12-month priority right from the first filing of a patent or utility model application in a Paris Convention state or WTO member. Article 88 covers how priority is claimed, multiple priorities and partial priority. Article 89 gives the effect: for novelty and for conflicts between applications, the priority date counts as the filing date.

Priority attaches only to the “same invention”. G 2/98 sets the test: the skilled person must be able to derive the subject matter of the claim directly and unambiguously, using common general knowledge, from the earlier application as a whole. It is the same strict standard as for added matter, so a broadened or reworded claim can lose priority.

A claim can enjoy partial priority. Under G 1/15, a generic “or” claim is entitled to priority for the alternatives that the priority document disclosed directly, or at least implicitly, unambiguously and in an enabling way. Article 88(2) also allows several priorities, including for one claim.

The priority must come from the first application for the invention (Article 87(1) and (4)). A later application in the same state counts as the first only if the earlier one was withdrawn, abandoned or refused before publication, without rights outstanding and without having served as a priority basis.

Who may claim priority matters too. G 1/22 and G 2/22 (10 October 2023) confirmed that the EPO can assess entitlement, but applied a rebuttable presumption that the applicant claiming priority is entitled. In a joint PCT filing by A and B, the joint filing implies an agreement that B may rely on A's priority unless there are substantial indications to the contrary.

If the priority year is missed despite all due care, re-establishment can be requested, but only within two months of the end of the priority period (Rule 136(1)), so the absolute outer limit is 14 months.

Deadlines and fees

Key decisions

• G 2/98 : Priority is acknowledged only if the skilled person can derive the claimed subject matter directly and unambiguously, using common general knowledge, from the previous application as a whole.
• G 1/15 : Partial priority cannot be refused for a generic “or” claim, provided the alternative was disclosed for the first time, directly or implicitly, unambiguously and in an enabling way in the priority document.
• G 1/22 and G 2/22 (Entitlement to priority) : The EPO may assess entitlement to priority, under a rebuttable presumption that the applicant claiming it is entitled, including for PCT applications and where the applicants differ.
• G 3/93 (Priority interval) : Where priority is invalid, a document published in the priority year is citable prior art against the application.

Common objections

Claim not entitled to priority

Usually because a feature was added or generalised after the priority filing. Check whether the claim, or part of it under G 1/15, is derivable from the priority document; otherwise find out what was published in the priority year.

Priority document not the first application

Raised when an earlier filing by the same applicant for the same invention exists. The cure is limited to Article 87(4); otherwise the later date counts.

Entitlement challenged

Typically where the priority applicant and the European applicant differ. Keep assignment documents, and record transfers of priority rights before the European filing.

Drafting and prosecution tips

• Make the priority filing as complete as possible, with claims, examples and fallback positions, because only what it discloses gets the earlier date.
• When the European application adds new matter, keep the original wording available as alternatives so that partial priority remains possible.
• Record any transfer of the right to claim priority in writing before the European or PCT application is filed.