EU Prospectus Regulation – ESMA guidelines on supplements which introduce new securities to a base prospectus

What has happened?

On 9 September 2026, ESMA published Guidelines on supplements which introduce new securities to a base prospectus.

The Guidelines fulfil a specific ESMA mandate under the EU Prospectus Regulation, deriving from the Article 23(4a) general prohibition¹  on issuers introducing a new type of security under a base prospectus that does not already contain disclosure for that security. ESMA consulted on proposed Guidelines in February 2025.

They are intended to harmonise divergent market practices and interpretations that have developed over time, including between competent authorities. They will become effective two months after publication on the ESMA website in all the official languages of the EU.

Summary of Guidelines

• Guideline 1: if a supplement involves disclosure from one of the annexes to the EU PR Regulation that did not apply to the securities included in the base prospectus, the supplement should be treated as introducing a new type of security.
• Guideline 2: where a base prospectus contains disclosure about securities giving rise to payment or delivery obligations linked to an underlying asset, a supplement may include disclosure about these types of underlying if the same type of underlying is already described in the base prospectus.
• Guideline 3: refers to a base prospectus describing asset-backed securities and provides that a supplement should not be used to introduce disclosure in relation to a new obligor or entity guaranteeing the obligations.
• Guideline 4: provides that a supplement should not be used to add disclosure in relation to sustainability-linked non-equity securities if sustainability-linked non-equity securities were not previously included in the base prospectus.

Supplementing a base prospectus to introduce new terms and conditions

Under the EU Prospectus Regulation, where a significant new factor relating to the information included in a prospectus arises after the prospectus has been approved, that new factor must be described in a supplement to the prospectus without delay. However, the EU Prospectus Regulation also provides that a supplement to a base prospectus may not be used to introduce a new type of security for which the necessary information has not been included in that base prospectus (unless doing so is necessary to comply with bank regulatory capital requirements).

These requirements have given rise to uncertainty, and diverging interpretations amongst competent authorities, as to the circumstances in which a supplement to a base prospectus may be used to introduce new features to the terms and conditions of securities described in the base prospectus without being considered to introduce a new type of security that is not already described in the base prospectus. As a result, Article 23(8) was inserted into the EU Prospectus Regulation by the 2024 Listing Act amendments requiring ESMA to develop guidelines to specify the circumstances in which a supplement is to be considered to introduce a new type of security that is not already described in a base prospectus.

Following a public consultation in 2025, on 9 September 2026 ESMA published its Final Report, containing four Guidelines on supplements which introduce new securities to a base prospectus. These Guidelines are intended to assist competent authorities and financial market participants in resolving the uncertainty described above.

Securities note annexes

Guideline 1 refers to the following annexes in Commission Delegated Regulation (EU) 2019/980 (the EU PR Regulation):

• Annex 17 – Securities giving rise to payment or delivery obligations linked to an underlying asset
• Annex 18 – Underlying share
• Annex 19 – Asset-backed securities
• Annex 21 – Guarantees

It provides that if a supplement involves disclosure from one of these annexes that did not apply to the securities included in the base prospectus, the supplement should be treated as introducing a new type of security and should not be approved by the relevant competent authority: a new base prospectus should be required instead.

Payment or delivery obligations linked to an underlying asset

Guideline 1 is refined by Guideline 2 which refers to a base prospectus which contains disclosure about the following types of underlying in accordance with Annex 17 of the EU PR Regulation (Securities giving rise to payment or delivery obligations linked to an underlying asset):

• an equity security
• a non-equity security
• a reference entity or reference obligation (for credit linked securities)
• an index
• an interest rate
• a commodity
• crypto-asset
• a basket of underlying
• some other underlying which does not fall within the categories specified above.

Guideline 2 provides that a supplement may include disclosure about these types of underlying if the same type of underlying is already described in the base prospectus. For example, if a base prospectus includes “index” as a possible type of underlying, disclosure on new proprietary indices may be added via a supplement as this is not a new type of underlying based on this approach. By contrast, a supplement should not include a commodity if the base prospectus does not include commodities as a type of underlying. However, if the underlying is a reference entity as referred to in Item 2.2.2 (a)(i) of Annex 17, Guideline 2 provides that a supplement should not be used to introduce disclosure in relation to a new entity unless the relevant disclosure is incorporated by reference using an approved and valid registration document.

Asset-backed securities

Guideline 3 refers to Annex 19 of the EU PR Regulation (Asset-backed securities) and provides that a supplement should not be used to introduce disclosure in relation to a new obligor or entity guaranteeing the obligations as referred to in item 2.2.11(a), new equity disclosure as referred to in item 2.2.16, or new disclosure for the reference asset or underlying as required by items 3.6(a) or (c).

Green bonds

Guideline 4 provides that a supplement should not be used to add disclosure in relation to sustainability-linked non-equity securities if sustainability-linked non-equity securities were not previously included in the base prospectus. However, disclosure in relation to (i) non-equity securities with ESG-related use of proceeds or (ii) structured non-equity securities advertised as having an ESG component or pursuing an ESG objective, may be added to the base prospectus using a supplement.

Next steps

The Guidelines are now being translated into the official EU languages and they will become effective two months after their publication on ESMA’s website in all the official languages.

Authors: Anna Delgado, Partner; Mike Logie, Partner; Tim Morris, Consultant, Expertise