Divisional applications at the European Patent Office

A European divisional application is a patent application that has been divided out of an earlier (parent) application.  It inherits the priority and filing dates of the parent application but is treated as a separate filing and can be prosecuted independently.

In this article, we explore common reasons for filing European divisional applications, outline the relevant pre-filing and filing formalities, and share practical tips to keep in mind when planning your next move before the EPO.

1.            Why file European divisional applications?

The most straightforward reason for filing a divisional application is to pursue protection for embodiments not covered in the parent application.  For instance, if a lack of unity objection is raised during prosecution, one or more ‘inventions’ may need to be deleted from the claims and thus cannot be pursued in the parent application.  If the excised subject matter is commercially valuable, filing one or more divisional applications is necessary to keep it in play.

The second reason is to safeguard a particular European patent family against the actions of third parties.  For instance, if someone has shown interest in the currently pending (parent) application (e.g. by filing third party observations), then filing a divisional application might be a good move to protect the patent family in Europe in the event that the parent European patent is opposed.

Another reason is, simply, to keep the options open.   Filing a divisional maintains pendency before the EPO, and this can be useful, whether to keep third parties guessing as to your next moves or retain flexibility as prosecution evolves.  For example:

(a)           if the parent case is cruising towards refusal (e.g. upcoming oral proceedings before the Examining Division with no prospect of success), filing a divisional application offers an opportunity to reset and reframe your prosecution strategy;

(b)           it may be desirable to tailor protection for different validation strategies and different litigation fora (e.g. parent case - narrower claims + Unitary Patent vs. divisional - broader claims + opt-out of the jurisdiction of the UPC + national validation); or

(c)           different speed/prosecution strategies (parent case - accelerated prosecution to get a quick grant of narrow, commercially relevant claim scope  vs. divisional case – slow prosecution, broad claim scope, keeping options open).

2.            When can a divisional application be filed?

A divisional application can only be filed while the corresponding European (parent) application is still pending.

Once an application has granted, it is no longer pending, and it is not possible to file a divisional application.  European divisional applications can thus be filed before the date of the publication of mention of grant in the European patent bulletin.  This date is indicated on the ‘decision to grant’, which typically issues from 1 to 3 weeks after a valid response to the Rule 71(3) EPC communication (‘notice of intention to grant’) has been filed.  Put simply, the deadline for filing an EP divisional is the day before the grant date.  This offers a lot of flexibility for applicants.  In practice, of course, it is best not to wait until the last minute with the filing.

What pending means is not always straightforward.  Below are some scenarios relevant to the timing of filing a divisional application.

Firstly, if an application is deemed to be withdrawn due to failure to timely respond to an examination report, it is possible to file a divisional application.  However, for the divisional to be considered as validly filed, it is necessary to then restore pendency of the existing (parent) application - in the case of a missed examination report deadline, it is necessary to make a valid request for further processing of the existing (parent) application.  Best practice is, perhaps, to restore pendency first, then file.  Conversely, if the applicant wishes to withdraw the parent application and file a divisional, it is best to do the latter first, then the former.

Secondly, if a renewal fee has not been paid on time, it is still possible to file a divisional application in the 6-month grace period for paying the renewal fee with a surcharge.  If it is decided not to proceed with the existing (parent) application (i.e. if the missed renewal fee is not paid within the grace period), the divisional is still considered to have been validly filed.

An interesting case of the timing of filing divisional applications relates to refusals during examination.  If an application has been refused by the Examining Division, the date of the decision to refuse starts a 2-month period in which to file a notice of appeal against the decision.  It is possible to file a divisional application in this period, even if the applicant does not wish to file a notice of appeal.  If a notice of appeal is filed but no divisional is filed, it is still possible to file the divisional in the 4-month period (from the date of the decision) for filing grounds of appeal.  If the grounds are filed but no divisional is filed, it is still possible to file the divisional before the termination of appeal proceedings.                              

3.            No lack of unity objection has been raised during prosecution – can a divisional application still be filed?

Indeed.  Before the EPO, lack of unity is not a prerequisite for filing a divisional application (in contrast with some other jurisdictions).

4.            What to bear in mind regarding the claims and the description of a divisional application?

It is important to be aware of the added subject matter requirements at the EPO.  A divisional application cannot contain subject matter that extends beyond the content of the parent application as originally filed. And, of course, any amendments made during prosecution of a divisional application cannot introduce subject matter that extends beyond the content of the divisional as filed.

Accordingly:

(a)           a European divisional application cannot be used to pursue new features of, or improvements to, an invention disclosed in the parent application, unless those features/improvements can be directly and unambiguously derived from the text of the parent application as filed; and

(b)           once the divisional application has been filed, the applicant is bound by the text of the application as filed.  It is thus critical to ensure that the entire content of the parent application as originally filed ends up in the divisional application.  There is no way to remedy any mishaps here, e.g. if figures of the parent are accidentally omitted on filing of the divisional.

Regarding point (b), when preparing the specification for a divisional application, EPO representatives often take the claims of the parent application as filed and present them as further ‘embodiments’ of the specification (or something similar) at the end of the description.

This is good practice, and is done with a view to ensuring that no subject matter is lost when the divisional application is filed.  In some cases, the claims of the parent application as originally filed contain subject matter that is not disclosed in the description of the application.  In that scenario, if the claims of the divisional application are drafted from scratch, there is a risk that some of the subject matter of the parent case does not make it to the text of the divisional application.  Presenting the claims of the parent case as ‘embodiments’ in the description effectively eliminates that risk.

On a related point, European divisional applications are effectively treated as a direct European filing.  Accordingly, excess claim fees, if due, are payable within one month of (i) the filing date (if claims are included on filing) or (ii) the date of receipt of claims (if supplied after filing).  There is no opportunity to amend the claims early during the procedure (unlike on the EPO regional phase entry).  For this reason, applicants tend to go for 15 claims when filing divisional applications at the EPO.

Finally, applicants can take advantage of the option of omitting the claims on filing of the divisional application and filing them later, when responding to a deficiency notice from the EPO.  This typically gives applicants about 2.5 months of extra time to submit the claims, and can be useful if more time is needed to decided on what subject matter to pursue in the divisional. Again, any submitted claims cannot add subject matter that extends beyond the content of the parent and divisional applications as originally filed.  It is also important to remember to pay the fee for excess pages of specification within one month of filing of the set of claims.

5.            What about the cost considerations of filing EP divisionals?

A European divisional application inherits the filing date of the parent case, and any accumulated renewal fees (calculated based on the filing date) are due on filing of the divisional application.  Thus, filing a divisional late in the patent term may incur substantial costs at the outset – about 10k EUR in renewal fees alone if filed around the 10th year of patent term.

The EPO also applies special fees to divisional applications depending on what case they have been divided out from.  Any divisionals filed whilst the first (original) application is pending are called ‘first generation divisionals’, and no special fee is payable in that instance.

However, any divisional applications filed whilst a first generation divisional application is pending are termed ‘second generation divisionals’, as they are divided out of the first generation divisional.  The fee for a second generation divisional application is currently 235 EUR.  There are a few more tiers of fees, up to the ‘fifth and subsequent generations’ divisional cases (currently 955 EUR).

Finally, if the subject matter pursued in the divisional corresponds to that searched on the parent application (so that the search report on the divisional can be based on that prepared for the parent case), it might be possible to get a refund of the search fee (currently 1520 EUR).

6.            What about double-patenting?

The recent change to the Guidelines for Examination at the European Patent Office signals the shift in EPO practice regarding double-patenting.  In the 2025 edition of the Guidelines, the following statement was introduced:

However, when, for example, the subject-matter of claim 1 in an application is the same as that of a dependent claim in a granted patent held by the same applicant, an objection of double patenting will be raised (see T 1128/19; emphasis added).

Thus, some careful consideration might be necessary before filing a divisional application.  For instance, if the parent case claims a class of chemical compounds per se and contains a dependent claim directed to a compound (per se) of interest, it seems that it will not be possible to pursue an independent claim directed to that compound per se in a divisional application.  If the parent case is still pending and a divisional along the lines discussed above is desired, it might be best to amend or delete the relevant dependent claim prior to filing the divisional application.

If you have any questions on EPO prosecution strategy, please feel free to get in touch.  

This article is for general information only and is not intended to constitute legal advice. If you would like tailored advice on a specific matter, please do not hesitate to contact me.