SIGN UP TO OUR EZINE
Choosing an International Searching Authority (ISA)
When filing an international application under the Patent Cooperation Treaty (PCT), applicants can choose where the search and examination steps are conducted. At the moment, applicants filing with IP Australia have a choice between IP Australia and the Korean IP Office as the International Search Authority (ISA). New Zealand applicants are able to choose from IP Australia, the Korean IP Office, the United States Patent and Trademark Office and the European Patent Office.
IP Australia has recently announced a 2-year pilot programme which will allow applicants filing PCT applications from Australia to also choose the European Patent Office (EPO) as the International Searching Authority (ISA) and the International Preliminary Examining Authority (IPEA) from 2026. With this additional option it is a good time to review some factors which may be relevant when choosing an ISA.
Factors to consider when choosing an ISA/IPEA
1. Market
Choosing the ISA/IPEA of a jurisdiction where you are most likely to enter the National or Regional phase will give you a good idea how examination (in that jurisdiction) might proceed.
2. Immediate Cost
Different ISAs charge different search fees. These can vary significantly. ISAs with a different national language may also require a translated specification, incurring translation fees at an early stage of the application process.
3. Downstream Cost
Many jurisdictions have discounts in the national phase if that particular Office conducted the preliminary examination. For example, IP Australia offers a roughly 30% discount on examination fees if IP Australia acted as the ISA.
The EPO conducts a supplementary search for any PCT applications entering the regional phase in Europe. However, where the EPO acted as the ISA, then the EPO does not conduct this supplementary search, eliminating the search fee. There is also a 75% discount on the examination fee if a Chapter II Demand was filed with the EPO acting as the IPEA.
4. Speed
An ISA must provide their written opinion within:
- three months from the date of receipt of the search copy; or
- nine months from the priority date of the application, whichever is later.
However, some ISAs will establish a search opinion before others. If it is likely that you will need to spread out the costs of entering the national/regional phase, the speed at which an ISA is estimated to issue a search report should be taken into account.
5. International Preliminary Examination Authority choices
The choice of ISA can often determine who can act as an IPEA for the purposes of further argument/amendment during the international phase.
In particular, the EPO can only act as the IPEA if a “European” office acted as the ISA. As such, New Zealand and Australian PCT applicants must select the EPO as the ISA if they wish to the EPO to also act as the IPEA.
Make an active choice of an ISA for each patent application
These and other factors may change from case to case, thus it is important that an active choice is made on each occasion - rather than assuming that an ISA that was previously used is still correct. If you need any assistance or further information, please do not hesitate to contact us.
Charlene Lo - September 2025
To avoid missing out on important updates from the Henry Hughes IP team, subscribe to our quarterly newsletter here.
