PCT Newsletter 10/2021: Practical Advice

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.

Filing strategies:  factors to consider when deciding which International Searching Authority to choose where more than one Authority is competent

Q:  I am the sole applicant in an international application that I am going to file with a receiving Office for which there are several competent International Searching Authorities.  What are the main factors that I should take into account when deciding which Authority to select?

A: Each receiving Office specifies one or more International Searching Authorities (ISAs) and International Preliminary Examining Authorities (IPEAs) as competent to carry out international searches and international preliminary examination, respectively, on international applications filed with it (PCT Rule 35).  Where several ISAs/IPEAs are competent, you may choose between them (subject to any restrictions that will be discussed below).  For the sake of simplicity, we will refer only to ISAs and the international search procedure in this practical advice, and not to IPEAs and the international preliminary examination procedure. 

Please also note that if you file the international application with the International Bureau as receiving Office (RO/IB), your choice of competent ISA would be the same as you would normally have when filing with the national Office of the Contracting State of which you (or if there is more than one applicant, one of the applicants) are a resident or national, or the national Office or intergovernmental organization acting for that Contracting State (PCT Rule 35.3). 

You can find out which ISA (or ISAs) are competent for each receiving Office in Annex C of the PCT Applicant’s Guide.  Where two or more International Searching Authorities (ISAs) are competent to carry out the international search, you must indicate the Authority chosen in Box No. VII of the request form at the time of filing. 

The main points to consider before making this choice are outlined below.

Different ISAs may be available depending on the receiving Office used:  where the Contracting State of which you are a resident is different from the one of which you are a national, you may have a wider choice of receiving Offices with which to file the international application.  As each receiving Office specifies its own competent ISAs, you should carefully consider the available ISAs when selecting the receiving Office with which to file your international application.  And if in the future you have multiple applicants in an application with differing nationalities and residences, and file with RO/IB, you may have more competent ISAs to choose from since the choice will be the composite of all of the ISAs which would have been competent for any of the national or regional receiving Office which you could have used.

Languages accepted for international search:  your choice of ISA should consider the language or languages accepted by the ISA or ISAs that are competent to carry out the search on your international application.  You should preferably choose an ISA that accepts the language in which you are filing your international application if you want to avoid having to translate your international application specifically for the purposes of international search (PCT Rule 12.3).  The language or languages accepted by each ISA are shown in Annex D of the PCT Applicant’s Guide.

Search fee (and other related fees) charged by the ISA:  an important consideration for you may be the cost of having an international search carried out by a particular ISA.  Search fees and related fees are fixed by the ISA concerned, and can vary considerably.  Furthermore, some ISAs offer reductions in the search fee in certain situations based on their practices as national or regional Offices (in particular, for small- and medium‑sized entities or for applicants from low- or middle‑income economies), and some fees payable in the national/regional phase are reduced where a particular ISA has carried out the international search.  Information on the search fees and any reductions in the search fee, where applicable, can be found in Annex D of the PCT Applicant’s Guide, and information on any available reductions in the national fees can be found, where applicable, in the corresponding National Chapter of the PCT Applicant’s Guide.

Quality of the international search and timeliness of issuance of the international search reports (ISRs) and written opinions:  you may wish to consider the reputation of the ISA, its compliance with Chapter 21 of the PCT International Search and Preliminary Examination Guidelines (“Common Quality Framework for International Search and Preliminary Examination”), and its reliability in terms of timeliness in the issuance of their reports.  Useful resources that you may wish to consult for information on this are:

  • the PCT International Authority Quality Reports at: https://www.wipo.int/pct/en/quality/authorities.html, and
  • the timeliness statistics reproduced in the PCT Yearly Review (the latest edition is available at:

https://www.wipo.int/edocs/pubdocs/en/wipo_pub_901_2021.pdf (statistics on timeliness in transmitting ISRs to the IB can be found on pages 84 and 85). 

Subject matter that will not be searched by the ISA:  in accordance with PCT Rule 39, ISAs are not required to search an international application if its subject matter is listed in items (i) to (vi) of that Rule.  If your international application relates to any of those subject matters, you may wish to choose an ISA which has indicated that it will search the subject matter of your application.  Further information is available, for each ISA, in the PCT Applicant’s Guide, Annex D.

Whether or not to have a search carried out by an ISA that is different from the Office which searched the earlier national filing:  if you are claiming priority of an earlier application (whether it be a national, regional or international application), and the Office that searched the earlier application is also a competent ISA, you may wish to select the same Office as ISA if this may result in receiving the search results more quickly, or in order to benefit from any possible fee reductions.  Also, in some cases, it may be possible to make use of the so‑called PCT Direct service before certain Offices (currently, this is available at the European Patent Office, the Finnish Patent and Registration Office, the Israel Patent Office and the Spanish Patent and Trademark Office), whereby an applicant filing an international application with an Office offering the PCT Direct Service which claims priority from an earlier application already searched by that Office, may submit informal comments to respond to any objections raised in the search report and written opinion drawn up in relation to the priority application.

Alternatively, you may prefer to have the search carried out by another ISA for a different perspective on the international search, for example, selecting an ISA based on the language expertise of the search examiners or particular document collections that an ISA may search beyond the PCT minimum documentation.

Limitations on the selection of the IPEA:  given that some IPEAs will carry out an international preliminary examination only on an application for which they, or another specified ISA, carried out the international search, this may affect your choice of ISA if you are likely to want to request a particular IPEA to carry out the international preliminary examination.

Consideration of prior art:  if you are going to seek patent protection only in a specific country or region, it may be useful, where possible, to choose an ISA that would search prior art that is particularly relevant to that region.  For example, if protection is sought in the Republic of Korea, it may be useful to choose ISA/KR (if possible) as that Office may find relevant prior art in Korean, which may not be accessible to other ISAs for language reasons.  Please also bear in mind that if you enter the national phase at the same Office that produced a positive ISR when it acted as the ISA on your international application, it may be quicker to obtain positive results before that Office upon national examination.   

Limitations of international searches by some ISAs:  some ISAs have limited the number of international applications that they will search where the international application has been filed with certain receiving Offices.  For example the Australian Patent Office and the Israel Patent Office, in their capacities as ISAs, have limited the number of international applications that they will search where the application was filed with the United States Patent and Trademark Office as receiving Office.  Any such restrictions are indicated in the PCT Applicant’s Guide (please refer to the part of Annex C relating to the competent receiving Office concerned).

Ability to make use of the Patent Prosecution Highway:  if you wish to request accelerated examination of your application in the national phase by requesting one or more national Offices to accelerate the processing of your application using the PCT‑Patent Prosecution Highway (PCT‑PPH) work-sharing scheme, you should check which national (or regional) Offices have PCT‑PPH agreements with the competent ISAs concerned.  For further information on bilateral or plurilateral agreements, please consult the PCT-PPH Program page at: 


and refer to the “Practical Advice” in PCT Newsletter No. 09/2021 at:


Whether an ISA also offers supplementary international search (SIS):  it is recalled that you can, at any point in the international phase, and subject to extra fees (the supplementary search fee and the supplementary search handling fee), request an SIS by any of the 10 Authorities specified for supplementary search (SISA) that currently offer this service.  Your choice of SISA does not depend on the receiving Office with which you file the international application, but the SISA must be different from the Authority that has performed the international search.  If you are planning to request SIS, this could influence your choice of ISA to carry out your international search, as you would not be able to choose the same ISA as the SISA.