During the summer break, the Issuers Committee of SIX Exchange Regulation (SER) updated its Circular No. 1 (Circular No. 1) on ad hoc publicity. The updates of June 28, 2023 relate mainly to the duty to label ad hoc announcements as such («flagging») and the content of ad hoc announcements. Similarly, SER has published several communiqués over the course of the last year providing guidance on its practice and interpretation of the applicable rules.
Under the ad hoc publicity rules, ad hoc announcements must be «flagged» as such. The updated Circular No. 1 reiterated the principle that it is not permitted to flag «pure marketing announcements» or mere repetitions of previously published price-sensitive facts as ad hoc announcements. In addition, the Circular No. 1 introduced a new paragraph stating that the «mixing of price-sensitive facts with pure marketing announcements in an ad hoc announcement is not permitted». These statements raise a number of important questions, which we will discuss below.
Relatedly, SER&#8217;s Communiqué 4/2022 dated July 7, 2022 pointed out that «important» facts such as updates to the financial calendar or invitations to and results of general shareholders meetings must not be published as ad hoc announcements unless those facts are indeed price-sensitive, which must be assessed by the issuer in an ex ante case-by-case analysis.
There are several key take-aways from the above:
<ol>
<li>As regards the scope of ad hoc announcements, SER seems to be raising the bar. The old practitioner&#8217;s rule of «in doubt, pro ad hoc» no longer applies. Information, even if it is important for all market participants, must not be disseminated in an ad hoc announcement unless the issuer concludes ex ante that the information in this specific case qualifies as price-sensitive fact as defined in the SIX rules. For example, the results of a general shareholders meeting that approves all non-controversial proposals of the board of directors are – absent special circumstances – not price-sensitive and must therefore not be published as an ad hoc announcement.</li>
<li>It may no longer be permissible to include both price-sensitive facts and other information in the same ad hoc announcement (no «mixing»).
<ol>
<li>While the updated Circular No. 1 declares the mixing of a pure marketing announcement with price-sensitive facts to be inadmissible, we believe that a more differentiated approach is warranted. The content of ad hoc announcements must comply with the SIX rules, which provide that ad hoc announcements must not only be factual and clear, but also complete, and be «formulated in such a way that the reasonable market participant can form an opinion as to the extent to which the content is price-sensitive» (15 paras. 1 and 2 Directive Ad hoc Publicity, DAH).</li>
<li>Accordingly, any additional information in the ad hoc announcement that is necessary or helpful for the market participant to analyze and comprehend the price-sensitive fact must be permissible. Such additional information must have a factual connection (Sachzusammenhang) with the price-sensitive fact and allow market participants to fully assess the content of the ad hoc announcement without recourse to other sources.</li>
<li>To give a few examples, in line with the above principle, earnings releases may contain prose commentary (be it a quote from the CEO or otherwise) or detailed financial information in addition to the price-sensitive headline figures. Ad hoc announcements of M&amp;A transactions may contain background information as to the transaction, its rationale and expected benefits, the parties involved etc. Finally, ad hoc announcements of clinical trial results may contain detailed information on the relevant study and product, its benefits for the patients, potential indications etc. The general «about [issuer]», «about [counterparty]» or «about [product]» information, «for more information» or similar links, contact details, information on upcoming investor relations or other key dates as well as similar information at the bottom of press releases may in our view also continue to be included in ad hoc releases.</li>
<li>Financial announcements such as the annual results that are «per se» price-sensitive (art. 4 para. 2 DAH) may contain all information that is also included in the report, whether or not this particular information is in fact price-sensitive.</li>
<li>Announcing two or more price-sensitive facts in one ad hoc announcement continues to be permissible. For example, a transaction signed on the same date as the earnings release may be announced in (or together with) the earnings release.</li>
</ol>
</li>
<li>While a mere repetition of price-sensitive facts that have already been disseminated in an ad hoc announcement is – of course – not permitted, it is still permissible to repeat such facts in subsequent ad hoc announcements about new price-sensitive facts if necessary or helpful for the context. For example, an ad hoc announcement of the (price-sensitive) closing of a transaction may again include the key facts already published in the ad hoc announcement of the signing.</li>
<li>Although the Circular No. 1 now states that the flag «must show the wording specified in the LR», i.e., «Ad hoc announcement pursuant to Art. 53 LR», it continues to be permissible to spell out the referenced legal basis (e.g., «Listing Rules» instead of «LR») or include a reference to the SIX Swiss Exchange (which may be helpful for companies with multiple listings). Accordingly, SER has not amended its FAQ dated January 1, 2022 on this point.</li>
</ol>
Overall, issuers will have to analyze (more) carefully in the future what information can (or must) be included in ad hoc announcements and what information must be published in separate «normal» press releases.
* * *
<h3>Further Information and Useful Links</h3>
The <a href="https://www.ser-ag.com/dam/downloads/regulation/listing/circulars/ic-cir1-en.pdf">updated Circular No. 1 of the Issuers Committee</a> dated June 28, 2023 specifies the revised provisions. <a href="https://www.ser-ag.com/dam/downloads/publication/commentaries/2022-03-21-guideline-dah-en.pdf">SER&#8217;s guidelines (formerly: commentary) on the ad hoc-publicity directive</a> dated March 21, 2022 as well as its <a href="https://www.ser-ag.com/dam/downloads/publication/news/Mailings/faq_kr_rlahp_cg_en.pdf">Answers to Frequently Asked Questions (FAQ)</a> dated January 1, 2022 provide helpful guidance for the interpretation of the rules.
Further helpful guidance can be found in Communiqués published by SER from time to time, see, e.g., the <a href="https://www.ser-ag.com/dam/downloads/regulation/listing/communiques-six-exchange-regulation/ser202302-en.pdf">Communiqué No. 2/2023</a> dated February 16, 2023 and the <a href="https://www.ser-ag.com/dam/downloads/regulation/listing/communiques-six-exchange-regulation/ser202204-en.pdf">Communiqué No. 4/2022</a> dated July 7, 2022.
Information on the last general revision of the SIX rules on ad hoc publicity in 2021 can be found <a href="https://www.homburger.ch/en/insights/revised-six-rules-on-ad-hoc-publicity">here (in English)</a> and <a href="https://www.homburger.ch/api/ms/2021/07/_/Revidierte-Ad-Hoc-Regularien-_-GesKR-2-2021.pdf">here (in German)</a>.

Homburger Bulletin

Recent Updates to SIX Rules on Ad Hoc Publicity

<h4>Key Changes</h4>
Abolition of «per se» price-sensitive facts
Subject to certain exceptions, the rules on ad hoc publicity of SIX Exchange Regulation (SER) require that issuers disclose price-sensitive facts (also known as material non-public information) that have arisen in their sphere of activity. Disclosure must take place without delay through specific information channels.
In its practice, SER assumed – without a regulatory basis – that certain facts were price-sensitive as such («per se»), i.e., that they always qualified as price-sensitive, irrespective of the circumstances of the individual case. The new rules now clarify that there are no such «per se» price-sensitive facts, with one exception: annual and interim financial reports must always be published by way of an ad hoc announcement. In all other cases, the issuer must decide on a case-by-case basis whether or not a fact is price-sensitive.
This rule change formally puts an end to the previous practice that all changes on the board of directors and top-level management are «per se» price-sensitive. In the future, the issuer must analyze the price-relevance of the specific change, as is the case for any other corporate event. This welcome clarification will simplify key personnel decisions and changes as well as negotiations with new executive committee members.
Labelling as «ad hoc announcement»
As from July 1, 2021, announcements that include price-sensitive facts must be explicitly labeled as «ad hoc announcement pursuant to article 53 LR» (so-called flagging). This requirement already applies in other European jurisdictions.
Announcements primarily for marketing purposes must not be published as ad hoc announcements. SER announced that misuse of flagging may be sanctioned.
Duty to establish internal rules governing the process for postponing disclosure
An issuer can postpone disclosure of certain price-sensitive facts (such as a planned M&amp;A transaction) if, among other things, it can ensure that the fact remains confidential. Under the new rules, issuers have to establish adequate and transparent internal rules or processes to this effect. In particular, the issuer must take organizational measures to ensure that confidential facts are disclosed only on a need to know basis.
In essence, issuers will need to adopt internal regulations with clearly defined processes and responsibilities. These regulations will require, for example, that insider lists be kept, confidentiality undertakings be obtained or information barriers and other technical safety measures be implemented. Similar obligations for issuers already exist under applicable insider trading laws. While this does not imply a major change in practice, it will nonetheless be important properly to document the internal rules and processes.
Separate index with the ad hoc announcements of the last 3 years on the issuer&#8217;s website
Going forward, ad hoc announcements must be posted in a separate directory on the issuer&#8217;s website, in chronological order and indicating the date of publication. Also, ad hoc announcements must be available for at least 3 years (previously 2 years).
Filing of ad hoc announcements exclusively via Connexor Reporting
As from October 1, 2021, issuers of primary listed equity securities must submit their ad hoc announcements to SER exclusively on the electronic reporting platform «Connexor Reporting».
Disclosure of general blackout periods in the corporate governance report
As a new rule, information on general blackout periods must be provided in the issuer&#8217;s corporate governance report, which forms part of the annual report. The revised SIX directive on information relating to corporate governance requires the disclosure of deadlines, addressees, scope and any exceptions to the general blackout periods, among other things. Special blackout periods, e.g., when ad hoc disclosure is postponed, do not need to be published.
<h4>Further changes</h4>
Revised definition of price sensitivity
The new definition reads as «facts whose disclosure is capable of triggering a significant change in market prices» (previously: «facts which are capable of triggering a significant change in market prices»). This welcome amendment aligns the definition of price sensitivity under the rules on ad hoc publicity with Swiss insider trading laws. It does, however, not entail a substantive change. Similarly, the deleted term «potentially» [price-sensitive] in the title is a purely editorial adjustment.
Issuer&#8217;s ex-ante assessment of price sensitivity as a discretionary decision
As previously, a price change is deemed significant if it is considerably greater than the usual fluctuations in the issuer&#8217;s share price. Under current practice, the issuer must assess ex ante whether or not a fact is price-sensitive in the specific case. This is now codified in the SIX rules. As today, there will be no fix percentage or numerical thresholds that indicate the existence of a price-sensitive fact.
The new rules further provide that the issuer makes its decision using its discretion, taking into account the company&#8217;s internal governance regulations. In our view, this gives issuers a decision-making latitude similar to the business judgment rule in corporate actions: if the decision-making process has been properly conducted and took place on an informed basis, SER should exercise restraint when reviewing the issuer&#8217;s decision. The company&#8217;s internal governance regulations can be observed, even if this means that the decision-making process requires some time, as long as the disclosure obligation is fulfilled in a «timely» manner.
Reference to the «reasonable» investor 
In connection with the assessment of price sensitivity, the new rules refer to the investment decision by a reasonable investor (previously: average investor). The term implies a rationally acting person with knowledge of the financial market, but not a professional investor. Again, this welcome amendment serves to align the rules on ad hoc publicity with Swiss insider trading laws and international standards.
<h4>Circular No. 1 of the Issuers Committee</h4>
The <a href="https://www.ser-ag.com/content/dam/serag/downloads/regulation/listing/circulars/IC-CIR1-en.pdf" target="_blank" rel="noopener">new circular no. 1 of the Issuers Committee dated March 10, 2021</a> contains helpful guidance for the interpretation of the amended rules. <a href="https://www.ser-ag.com/dam/downloads/publication/commentaries/2011-11-01-commentary-dah-en.pdf" target="_blank" rel="noopener">SER&#8217;s commentary on the ad hoc-publicity directive dated November 1, 2011</a> has not yet been updated.
The revised regulations can be downloaded at: <a href="https://www.ser-ag.com/content/dam/serag/downloads/regulation/listing/listing-rules/LR-REV-en.pdf" target="_blank" rel="noopener">Listing Rules</a>; <a href="https://www.ser-ag.com/content/dam/serag/downloads/regulation/listing/directives/DAH-REV-en.pdf" target="_blank" rel="noopener">Directive Ad hoc Publicity</a>; <a href="https://www.ser-ag.com/content/dam/serag/downloads/regulation/listing/directives/DCG-REV-en.pdf" target="_blank" rel="noopener">Directive Corporate Governance</a>.
<h4>Homburger Webinar</h4>
On June 9, 2021, we hosted a webinar on the new ad hoc publicity rules. You can download the slides <a href="https://cms.homburger.ch/wp-content/uploads/2021/06/Webinar_Revised-Ad-Hoc-Rules.pdf" target="_blank" rel="noopener">here</a> and watch the webcast here:

Revised SIX rules on ad hoc publicity

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Homburger advised OC Oerlikon on the completion of the divestment of its Barmag textile machinery business for manmade fibers to Rieter

On February 2, 2026, OC Oerlikon announced that it has completed the divestment of its Barmag textile machinery business for manmade fibers to Rieter at an enterprise value of CHF 850 m with an earn-out of up to CHF 100 m. With the closing of this transaction, Oerlikon becomes a pure-play surface technology company, serving a broad base of customers in demanding industries – from automotive, aerospace and energy to luxury, medical, defense and semiconductors – with a toolbox of high-tech surface technologies.
The Homburger team was led by Daniel Hasler (Corporate / M&amp;A) and included Anna Peter, Nicola Togni, Matthias Müller, Alessandro Samà and Fabio Gasser (all Corporate / M&amp;A), Dieter Grünblatt (Tax), Richard Stäuber and Nicolas Stocker (both Competition), Lorenzo Togni (Capital Markets) as well as Jürg Frick (Financing).

IP / IT

Homburger advises ABB on the carve-out and sale of its robotics division to SoftBank

On October 8, 2025, ABB Ltd announced it has signed an agreement to divest its robotics division to SoftBank Group Corp. for an enterprise value of USD 5.375 bn. ABB’s robotics business is one of the world’s leading robotics suppliers with a global customer base and approximately 7,000 employees. The sale is subject to a carve-out through a multi-jurisdictional reorganization which will conclude prior to closing. Completion is also subject to the receipt of customary regulatory clearances.
Homburger acts as Swiss counsel to ABB. The Homburger team includes Claude Lambert, Andreas Müller, Anna Peter, Estelle Piccard, Claudine Schär, Simone Schmid and Luca Ellenberger (all Corporate / M&amp;A), Reto Heuberger, Peter Müller and Juliette Buob (all Tax) as well as Andri Hess and Noëmie Beck-Schär (both IP/IT).

Capital Markets

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Homburger advises OPAP on its business combination with Allwyn

On October 13, 2025, Allwyn International AG and OPAP S.A. announced that their respective boards of directors have approved the business combination of Allwyn and OPAP through an all-share transaction that values the resulting entity at an equity value of EUR 16 bn. The Combined Company will be renamed Allwyn. It will remain listed on the Main Market of the Athens Stock Exchange and intends to pursue an additional listing on another leading international exchange such as London or in New York following closing.
The transaction will bring together two leading gaming operators, creating the second largest listed gaming entertainment company globally, with multiple diverse, fast-growing and market-leading positions across Europe, the United States and other international markets.
The Homburger team includes Anna Peter, Flavio Romerio and Bianca Nedwed (all Corporate / M&amp;A).

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Homburger advised OC Oerlikon on the completion of the divestment of its Barmag textile machinery business for manmade fibers to Rieter

Homburger advises ABB on the carve-out and sale of its robotics division to SoftBank

Homburger advises OPAP on its business combination with Allwyn

Recent Updates to SIX Rules on Ad Hoc Publicity

Revised SIX rules on ad hoc publicity

Highlights of the AGM season 2022

Revidierte Regularien zur Ad hoc-Publizität

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Homburger advised OC Oerlikon on the completion of the divestment of its Barmag textile machinery business for manmade fibers to Rieter

Homburger advises ABB on the carve-out and sale of its robotics division to SoftBank

Homburger advises OPAP on its business combination with Allwyn

Recent Updates to SIX Rules on Ad Hoc Publicity

Revised SIX rules on ad hoc publicity

Highlights of the AGM season 2022

Revidierte Regularien zur Ad hoc-Publizität

Corporate M&A 2020: Switzerland

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Anna Peter

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