PA 02/2010: Adding a priority claim which extends the period between the earliest priority date and the international filing date to over 12 months

WARNING: Although the information which follows was correct at the time of original publication in the PCT Newsletter, some information may no longer be applicable; for example, amendments may have been made to the PCT Regulations and Administrative Instructions, as well as to PCT Forms, since the PCT Newsletter concerned was published; changes to certain fees and references to certain publications may no longer be valid. Wherever there is a reference to a PCT Rule, please check carefully whether the Rule in force at the date of publication of the advice has since been amended.

Q:  I filed an international application on 25 January 2010, claiming the priority of an earlier national application filed on 11 May 2009. I have now realized that I omitted to claim the priority of an application I filed earlier than the date of the other claim, on 5 January 2009.  Is it possible to add that priority claim under PCT Rule 26bis.1, even though the period between the filing date of that earlier application and the international filing date exceeds 12 months?

A:  You are permitted under PCT Rule 26bis.1 to add a priority claim within a specified time limit (see below), even if the resulting new priority date would not fall within the 12‑month priority period (that is, it would be more than 12 months prior to the international filing date), provided that the time limit of 14 months from the (earliest) priority date has not expired.  In such a case, your new priority claim would remain in the application during the international phase, and all time limits which had not already expired would be calculated on the basis of that earlier priority claim.  However, whether that priority claim would be recognized by the designated/elected Offices (hereinafter:  “designated Offices”) in the national/regional phase would depend on your making a request for restoration of the right of priority, and how successful that request ultimately would be before those Offices.

Before you take any action to request the restoration of the right of priority (or at least at the same time as requesting the restoration of the right of priority), you must submit a notice under PCT Rule 26bis.1 requesting the addition of the missing priority claim.  In general, the time limit for submission of the notice is whichever of the following time limits expires later:

(a)     four months from the international filing date;  or

(b)     16 months from the priority date, or, where the addition of the missing priority date would cause a change in the priority date, 16 months from the priority date as so changed (whichever expires first).

In your case, the time limit under (a) (25 May 2010) expires later than the time limit under (b) (5 May 2010) therefore you would normally have until 25 May 2010 to add the missing claim.  However, it is important to note that if you are going to request the restoration of the right of priority before the receiving Office in the international phase, such a request must be filed within two months from the date on which the priority period will expire, which in your case, is by 5 March 2010.  Since you need to add the priority claim before, or at the same time as, you request the restoration of the right of priority, it is recommended that you request the addition of the priority claim as soon as possible, and in any case, before 5 March 2010 (see PCT Rules 26bis.3(c) and (e)).  It is recalled that the PCT Time Limit Calculator can be very useful when calculating time limits under the PCT.  It is available at:

Note that, as well as adding a priority claim, PCT Rule 26bis.1 can also be used to correct a priority claim, or to add any missing indication in a priority claim, for example, the date on which the earlier application was filed, the number of the earlier application or the country in which, or the Office with which, the earlier application was filed.  For further information on adding or correcting priority claims under PCT Rule 26bis.1, see the “Practical Advice” in PCT Newsletter No. 09/1998, and the PCT Applicant’s Guide, paragraphs 6.038 to 6.040 at, respectively:

As far as requesting the restoration of the right of priority is concerned, it is important to note that you may do this either during the international phase under PCT Rule 26bis.3 (“Restoration of Right of Priority by Receiving Office”) before the receiving Office within the above-mentioned two-month time limit, provided your receiving Office will accept requests for restoration of the right of priority, or you may request restoration in the national phase under PCT Rule 49ter.2 (“Restoration of Right of Priority by Designated Office”) directly with designated Offices which accept such requests.  As this is a complex subject, reference is made to the detailed explanations that were given in the “Practical Advice” published in PCT Newsletter Nos. 04/2007, 09/2009 and 10/2009 at, respectively:

as well as to the PCT Applicant’s Guide, paragraphs 5.062 to 5.069, at:


References: r_26bis_pct; r49ter_pct;

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