We have performed a limited assurance engagement on whether the below Sustainability Information in the Sustainability Report (“Report”) of POSCO (the “Company”) as of and for the year ended December 31, 2025 has been prepared in accordance with Criteria.

Based on the procedures performed and evidence obtained, nothing has come to our attention that causes us to believe that the Company has not complied as of and for the year ended December 31, 2025, in all material respects, with Criteria.

Our conclusion on the SMI does not extend to any other information that accompanies or contains the SMI and our report.

We conducted our engagement in accordance with International Standard on Assurance Engagements (ISAE) 3000 (Revised) ‘Assurance Engagements Other Than Audits or Reviews of Historical Financial Information’, issued by the International Auditing and Assurance Standards Board (IAASB). Our responsibilities under this standard are further described in the “Our responsibilities” section of our report. 

We have complied with the independence and other ethical requirements of the International Code of Ethics for Professional Accountants (including International Independence Standards) issued by the International Ethics Standards Board for Accountants (IESBA).

Our firm applies International Standard on Quality Management (ISQM) 1 ‘Quality Management for Firms that Perform Audits or Reviews of Financial Statements, or Other Assurance or Related Services Engagements’, issued by the IAASB. This standard 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.

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

Management of the `Company is responsible for:

The preparation of sustainability information requires management to establish or interpret the applicable criteria, determine the relevance of information to be included, and develop estimates and assumptions that affect the reported information. Entities may apply different but acceptable interpretations, judgments, and estimations. Sustainability information includes details about the company’s environmental, social, and governance (ESG) initiatives and goals, the anticipated future impact of events that have occurred or are expected to occur, and information regarding commitments and uncertainties. Actual results may differ significantly from management’s current assessments, as events and circumstances often do not unfold as expected.

We are responsible for:

We exercised professional judgment and maintained professional skepticism throughout the engagement. We designed and performed our procedures to obtain evidence about the SMI that is sufficient and appropriate to provide a basis for our conclusion. Our procedures selected depended on our understanding of the SMI and other engagement circumstances, and our consideration of areas

where material misstatements are likely to arise. In carrying out our engagement, the procedures we performed primarily consisted of

The 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.

Seoul, Korea