Legal framework
Where the International Searching Authority considers that the international application lacks unity of invention, it may invite the applicant to pay additional search fees. Under PCT Rule 40.1(ii), the applicant is invited to pay those fees within one month from the date of the invitation. The additional fees are payable directly to the International Searching Authority under PCT Rule 40.2(b).
For PCT time limits expressed in months, PCT Rule 80.2 provides that the period expires in the subsequent month on the day having the same number as the day of the relevant event. PCT Rule 80.5 extends a period expiring on a non-working day or official holiday of the relevant Office or organisation to the next subsequent day on which the relevant obstacle no longer exists.
For priority, PCT Article 8(2)(a) refers to Article 4 of the Paris Convention for the conditions and effect of a priority claim. Under Paris Convention Article 4C(1), the priority period for patents is twelve months.
Statement a)
False.
The invitation to pay the additional search fee is dated 1 September 2025. Under PCT Rule 40.1(ii), the additional search fee must be paid within one month from the date of the invitation. Applying PCT Rule 80.2, the period expires on 1 October 2025.
The fact that the invitation was received on 3 September 2025 does not move the deadline to 3 October 2025. There is no general PCT “ten-day rule” comparable to the former EPC notification rule.
Therefore, payment on 6 October 2025 would be too late.
Statement b)
True.
PCT-A was filed on 3 October 2024 without claiming priority. The twelve-month priority period therefore normally expires on 3 October 2025.
For a PCT filing made at the EPO as receiving Office, 3 October 2025 was a closing day for PCT purposes, because the EPO notice on 2025 closing days lists Day of German Unity, 3 October 2025, and states that the list applies for the purposes of PCT Rule 80.5. The period is therefore extended to the next working day, Monday 6 October 2025.
Thus, on 6 October 2025, it is still possible to file PCT-B validly claiming priority from PCT-A, provided the subject-matter of the second invention is disclosed in PCT-A.
Statement c)
False.
A supplementary international search may be requested only from an International Searching Authority competent to carry out such a supplementary search. Under PCT Rule 45bis.9(b), the International Searching Authority that carried out the international search for the application is not competent to carry out a supplementary international search for the same international application.
Here, the EPO already acted as ISA for PCT-A. Therefore, the EPO cannot carry out a supplementary international search for PCT-A. The statement is false.
Statement d)
True.
Under PCT Rule 40.2(b), additional search fees due under Article 17(3)(a) PCT are payable directly to the International Searching Authority.
Since the EPO acted as ISA, the additional search fee would be paid to the EPO as ISA.
Exam tip
For PCT non-unity, the deadline for additional search fees runs from the date of the invitation, not from receipt. Also distinguish an additional international search by the same ISA from a supplementary international search: the same Authority that acted as ISA cannot be chosen for supplementary international search under PCT Rule 45bis.9(b).
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