Independent assurance report

on selected indicators in the ESG Report 2024/25 to the Board of Directors of Sonova Holding AG, Stäfa.

Applicable criteria

The Group defined as applicable criteria (the Applicable Criteria):

• Global Reporting Initiative Sustainability Reporting Standards (GRI Standards). A summary of the standards is presented on the GRI website.
• SASB Standards for the Medical Equipment & Supplies industry. A summary of the standards is presented on the SASB website.
• ESRS Standards. The criteria and calculation principles are presented on the EFRAG website.
• The Groupʼs own methodology available in the relevant sections of the Report and in the chapter “Sustainability notes”.

Inherent limitations

The accuracy and completeness of selected indicators (including GHG emissions) are subject to inherent limitations given their nature and methods for determining, calculating and estimating such data. In addition, the quantification of the selected indicators is subject to inherent uncertainty because of incomplete scientific knowledge used to determine factors related to the emissions factors and the values needed to combine e.g., emissions of different gases. Additionally, GHG procedures are subject to estimation (or measurement) uncertainty resulting from the measurement and calculation processes used to quantify emissions within the bounds of existing scientific knowledge. Our assurance report should therefore be read in connection with the Groupʼs “Sustainability notes” chapter including its definitions and procedures on non-financial matters reporting therein.

Responsibility of the Board of Directors

The Board of Directors is responsible for the selection of the Applicable Criteria and for the preparation and presentation, in all material respects, of the selected indicators (including GHG emissions) in accordance with the Applicable Criteria. This responsibility includes the design, implementation, and maintenance of internal control relevant to the preparation of the Report that are free from material misstatement, whether due to fraud or error.

Independence and quality control

We have complied with the independence and other ethical requirements of the International Code of Ethics for Professional Accountants (including International Independence Standards) of the International Ethics Standards Board for Accountants (IESBA Code), which is founded on fundamental principles of integrity, objectivity, professional competence and due care, confidentiality and professional behavior.

Our firm applies International Standard on Quality Management 1, which requires the firm to design, implement and operate a system of quality management including policies or procedures regarding compliance with ethical requirements, professional standards and applicable legal and regulatory requirements.

Our responsibility

Our responsibility is to express a conclusion on the selected indicators (including GHG emissions) based on the evidence we have obtained. We conducted our limited assurance engagement in accordance with International Standard on Assurance Engagements (ISAE) 3000 Assurance Engagements Other than Audits or Reviews of Historical Financial Information. This standard requires that we plan and perform this engagement to obtain limited assurance about whether the selected indicators (including GHG emissions) are free from material misstatement, whether due to fraud or error.

Summary of work performed

Procedures performed in a limited assurance engagement vary in nature and timing from, and are less in extent than for a reasonable assurance engagement. Consequently, the level of assurance obtained in a limited assurance engagement is substantially lower than the assurance that would have been obtained had a reasonable assurance engagement been performed. Our procedures were designed to obtain a limited level of assurance on which to base our conclusion and do not provide all the evidence that would be required to provide a reasonable level of assurance.

Although we considered managementʼs internal controls when determining the nature and extent of our procedures, our assurance engagement was not designed to provide assurance on internal controls. Our procedures did not include testing controls or performing procedures relating to checking aggregation or calculation of data within IT systems.

Our limited assurance procedures included, amongst others, the following work:

• Assessment of the suitability of the Applicable Criteria and their consistent application
• Interviews with relevant personnel to understand the business and reporting process, including the sustainability strategy, principles and management
• Interviews with the Groupʼs key personnel to understand the sustainability or non-financial reporting system during the reporting period, including the process for collecting, collating and reporting the indicators and non-financial information
• Checking that the calculation criteria have been correctly applied in accordance with the methodologies outlined in the Applicable Criteria
• Analytical review procedures to support the reasonableness of the data
• Identifying and testing assumptions supporting calculations
• Testing, on a sample basis, underlying source information to check the accuracy of the data performed

We believe that the evidence we have obtained is sufficient and appropriate to provide a basis for our assurance conclusions.

Conclusion

Based on the procedures performed and the evidence obtained, nothing has come to our attention that causes us to believe that the selected indicators (including GHG emissions) in the Report of Sonova Holding AG for the reporting period from 1 April 2024 to 31 March 2025 have not been prepared, in all material respects, in accordance with the Applicable Criteria.

Ernst & Young Ltd