G 1/26 asks the EPO’s Enlarged Board of Appeal to settle a core question of claim interpretation: how far the description can shape a claim’s meaning, in particular when the EPO checks for added matter. The answers will decide which amendments survive examination and opposition for any European patent application, including those that enter the European phase from Latin America through the PCT. Until then, draft priority texts whose claims mean what you intend without help from the description.
Update (October 2026): on 3 September 2026 the Enlarged Board decided the separate referral G 1/25: the description must be adapted to amended claims only where an inconsistency leads to non-compliance with specific EPC provisions, including Article 123(2). G 1/26 remains pending and the deadline for third-party statements is still 30 November 2026. EPO, decision G 1/25.
Key takeaways
- The referral comes from interlocutory decision T 873/24 of 3 February 2026, in an opposition appeal between ArcelorMittal and POSCO over coated steel strips.
- The core issue is whether the description can narrow an ambiguous claim term when assessing added matter (Article 123(2) EPC).
- Third parties may file written statements until 30 November 2026, according to the EPO Official Journal of 31 July 2026.
- For applicants, the practical lesson is to define units, bases and key terms in the claims themselves.
What has been referred to the Enlarged Board in G 1/26?
The case concerns European patent EP 3 587 104, owned by ArcelorMittal and opposed by POSCO. Granted claim 1 lists the steel composition “by weight” and then requires that “the ratio of titanium to nitrogen is in excess of 3.42”, without saying whether that ratio is by weight or molar. According to the referring decision, the opposition division read the ratio as a weight ratio, also in view of the description; the opponent contested that reading. If both readings are technically sensible and only one has a basis in the application as filed, the claim may add matter.
Technical Board of Appeal 3.3.05 referred the questions on 3 February 2026; the EPO made the referral public in June 2026, and the Official Journal communication of 31 July 2026 (OJ EPO 2026, A37) invites third-party statements.
| Question | What it asks, in plain terms |
|---|---|
| 1 | When may a Board refer a question that is not strictly decisive for the case? |
| 2(a) | Does the rule that claims are the starting point prevent reading a feature disclosed only in the description into a granted claim, especially to narrow it? |
| 2(b) | If not, is interpretation one single exercise of reading the claims with the description and drawings, excluding only readings that clearly contradict the ordinary technical meaning? |
| 3(a) | For added matter under Article 123(2) EPC, must a claim term be tested against every technically sensible reading of the claim alone? |
| 3(b) | If not, is it enough that the reading established in light of the whole patent is directly and unambiguously derivable from the application as filed? |
Why G 1/24 did not settle claim interpretation for added matter
In G 1/24 (18 June 2025), the Enlarged Board held that the claims are the starting point and the basis for assessing patentability under Articles 52 to 57 EPC, and that the description and drawings must always be consulted to interpret them, not only when a claim is unclear. It did not say how that applies to Article 123(2) EPC, which prohibits amendments going beyond the application as filed.
Since then, as Carpmaels & Ransford summarised in June 2026, Boards have taken different routes: some test every technically sensible reading of the claim; others use the description to exclude incompatible readings but not to add restrictions; others treat claim and description as one interpretive exercise. In T 873/24, the first two routes would lead to a finding of added matter and the third would not. The EPO’s announcement of 11 June 2026 confirms that examining and opposition divisions keep applying the current Guidelines in the meantime.
What this means for your business
A Latin American applicant usually files first at home, in Spanish or Portuguese, and reaches the EPO through a PCT application that is later translated into English, French or German. Every ambiguity in that first text travels with the family, and G 1/26 will decide how much the description can rescue it. Our recommendation is to draft now as if the answer will be strict:
- State units and bases expressly in the claims: weight or molar, percentage of what, measured how.
- Define key terms in the description and use them consistently in the claims, without synonyms.
- Include fallback positions with literal support, such as narrower ranges and specific combinations, so later amendments have a clear basis.
- Check the translation against the original before European phase entry, and cite exact supporting passages for every later amendment.
If your family runs from a Latin American priority to the EPO and the national phases, our European and Latin American patent prosecution team can review the priority text and the claim set before the deadlines that matter.
Where companies get this wrong
- Relying on the description to fix the claim. Whatever G 1/26 decides, a claim that is clear on its own avoids the argument.
- Copying ratios or parameters from lab reports without stating the unit or the measuring method.
- Filing a short priority application and expecting to add detail at PCT or European phase, when Article 123(2) only allows what was originally disclosed.
- Letting different advisers handle the priority text, the PCT translation and the European amendments, so no one checks that the terms stay consistent.
These problems surface in opposition, years after filing; a single team coordinating the whole family can prevent them at the source.
Frequently asked questions
What is G 1/26 about?
G 1/26 is a referral to the EPO’s Enlarged Board of Appeal on claim interpretation. It asks whether the description can be read into a claim to narrow its meaning, and how claim terms should be interpreted when checking that an amendment does not add matter under Article 123(2) EPC.
Does G 1/26 stop European patent examinations or oppositions?
No. The EPO announced on 11 June 2026 that examination and opposition proceedings continue while the referral is pending, as it did for G 1/24 and G 1/25. Examining and opposition divisions keep applying the current Guidelines for Examination.
Can companies submit observations in G 1/26?
Yes. The Official Journal communication of 31 July 2026 invites third parties to file written statements by 30 November 2026, in English, French or German, quoting case number G 1/26 and addressed to the Registry of the Enlarged Board of Appeal.
Can IP Global Guard review our drafts with G 1/26 in mind?
Yes. We prepare and coordinate priority, PCT and European filings, working with European patent attorneys before the EPO and with qualified correspondents in Latin America. We can review terminology, units and fallback positions across the family before you file or enter the European phase, from a single point of contact.
How IP Global Guard can help you draft for the EPO
G 1/26 will set the rules, but the risk already exists: wording that seemed clear at home can be read in more than one way at the EPO. IP Global Guard, the IP services line of META Channel Corporation Limited, coordinates patent families across more than 25 jurisdictions in Europe, Latin America and Africa, with one strategy and one billing relationship.
Send us your priority application or PCT text and the date you plan to enter the European phase. We will check the claims and terminology against the questions in G 1/26 and coordinate the filings from a single point of contact. Contact our patent team.
This article is general information, not legal advice, and reflects the position on its publication date.
Sources
- EPO, Official Journal 2026, A37: communication from the Enlarged Board of Appeal concerning case G 1/26 (31 July 2026)
- EPO Technical Board of Appeal 3.3.05, interlocutory decision T 873/24 (3 February 2026)
- EPO, New referral G 1/26: further guidance sought on claim interpretation (11 June 2026)
- EPO Enlarged Board of Appeal, G 1/24 (18 June 2025)
- Carpmaels & Ransford, New EBA referral: G 1/26 (17 June 2026)
- EPO Enlarged Board of Appeal, G 1/25 (3 September 2026; update block only)
