Stakeholder Communication

Three types of surveys were distributed

ASEH has adopted a structured approach to ESG integration in accordance with GRI Standards. The company has identified 21 material ESG topics and systematically embedded them into three key analytical dimensions: stakeholder concern, operational impact, and external sustainability impact. Stakeholder feedback was gathered through a survey platform, ensuring broad and representative input. Concurrently, our management evaluated the operational implications of each ESG topic, while department heads and sustainability team members conducted impact assessments to determine the materiality and relevance of each issue.

2,721 Stakeholders participated in the Stakeholder Concern Survey

The degree of concern from stakeholders is a key factor in the process of determining the significance of our material issues, and the process is an important channel for us to communicate with our external stakeholders. This year, we designed a questionnaire on stakeholders’ degree of concern about sustainability issues that drew a total of 2,721 stakeholder responses. The respondents included employees (1,449), suppliers/contractors (851), communities (139), customers (103), and members of the government (51), media (37), shareholders (32), NGOs (30), and industry unions/ associations (29). To ensure a representative understanding of stakeholder expectations, ASE conducted an online survey engaging a diverse group of stakeholders. The five most critical ESG issues identified were: Occupational Health and Safety, Regulatory Compliance, Sustainable Manufacturing, Risk and Crisis Management, Human Rights Management. These findings reflect stakeholder priorities and serve as a strategic reference for shaping ASE’s sustainability roadmap.

175 Executives and members of the Corporate Sustainability Committee participated in the Organizational Operational Impact Survey

Sustainability is deeply embedded into ASEH’s core operational strategy and serves as a foundational principle of its ESG framework. To evaluate the integration and business relevance of ESG topics, 175 executives and members of the Corporate Sustainability Committee participated in a structured assessment process. The group duly assessed the impact of each ESG topic across four critical operational factors: Revenue Generation, Risk Exposure, Customer Satisfaction, Employee Engagement. This evaluation enabled the organization to prioritize ESG issues based on their direct influence on business performance. The five ESG topics identified as having the most significant operational impact were: Regulatory Compliance, Customer Relationship Management, Risk and Crisis Management, Business Ethics, Data Privacy and Security. The data-driven approach ensures that ASEH’s sustainability initiatives are closely aligned with its strategic business objectives. It also supports better resource allocation and the development of targeted ESG strategies that drive both operational efficiency and long-term value creation.

40 Department heads and sustainability team members participated in the External Sustainability Impact Survey

ASEH applies internationally recognized methodologies to assess external sustainability impacts, drawing from frameworks developed by the Value Balancing Alliance (VBA), Harvard Business School’s Impact-Weighted Accounts Initiative (IWAI), and the London Benchmarking Group (LBG). These methodologies encompass economic, environmental, and social dimensions, identifying a total of 22 relevant sustainability development impacts:  5 economic impacts, 6 environmental impacts, 11 social impacts. We have engaged 40 department heads and core sustainability team members to help identify 9 external impacts relevant to ASEH based on five key criteria: positive vs. negative, actual vs. potential impact, severity (scale), scope of impact, irremediability, and likelihood of future occurrence. In addition, participants were requested to leverage on their experiences to pinpoint which are the company’s sustainability issues that are driving these external impacts. 5 sustainability issues, listed according to the degree of impact, were duly identified. These are Sustainable Manufacturing, Sustainable Supply Chain, Climate Strategy, Energy Management and Risks and Crisis Management.

The company establishes multiple layers of assessment frameworks to ensure the objectivity of the findings from the analysis of material sustainability issues. This approach integrates both quantitative and qualitative assessments, ensuring the alignment of material issues with the company’s long-term strategic direction. The quantitative assessment is based on the outcomes of three targeted surveys, evaluating: Stakeholder concerns, Operational impacts on the business, External sustainability impacts.

The qualitative assessment incorporates internal strategic considerations, including:

• Alignment with ASE’s long-term sustainability objectives

• Relevance to executive compensation structures

Three main screening criteria

To ensure consistency and objectivity, ASE established three screening criteria for material topic selection:

• Criteria 1: Collecting insights from stakeholder, operational, and external impact assessments

• Criteria 2: Establishment of long-term corporate goals

• Criteria 3: Linking executive performance and compensation metrics

Topics meeting at least two out of the three criteria are prioritized as material issues. The 2024 materiality matrix was finalized after a thorough internal review of the findings by the company’s management and recommendations from expert consultants. The matrix serves as the foundation of ASE’s 2024 Sustainability Report, reflecting both stakeholder expectations and the company’s strategic ESG commitments.

Following a structured evaluation process and defined selection criteria, the company identified and prioritized 17 material sustainability issues in the following sequence:

1. Climate Strategy
2. Sustainable Supply Chain
3. Regulatory Compliance
4. Water Resource Management
5. Energy Management
6. Sustainable Manufacturing
7. Business Ethics
8. Customer Relationship Management
9. Talent Attraction and Retention
10. Occupational Health and Safety
11. Social Engagement
12. Innovation Management
13. Waste and Circular Reuse
14. Information Security Management
15. Human Rights Management
16. Diversity and Inclusion
17. Talent Development

17 Key Issues, 4 Major Impact Stages, Corresponding to 23 Topics Topics

These issues were formally presented to the Board of Directors and validated based on their relevance and impact across four key stages of the ESG value chain: upstream procurement, manufacturing facilities, downstream impact, and external value chain stages.

Each issue was subsequently mapped across 19 GRI Standards and 4 ASE-specific topics, with disclosures adhering to the principles of double materiality. The report outlines the impact scope, management approach, and associated risks for each material topic. Non-material issues were also disclosed in the sustainability report to ensure transparency in stakeholder communication.

The ASE Holdings Corporate Sustainability and Information Security Committee (CSISC) conducts annual reviews to track milestones and oversee each business units’ progress. In addition, the internal sustainability committees within each of our three major subsidiaries regularly convene to closely monitor the progress of these goals and track emerging sustainability trends.

42 Long-term Goals

To enhance the company’s sustainability impact, we have established clear commitments for each material topic and set 42 long-term sustainability goals for 2030. These goals are being progressively implemented through various projects and initiatives across our global sites.

4 Dedicated sustainability committees

• ASE Holdings Corporate Sustainability and Information Security Committee (CSISC)

• ASE Corporate Sustainability Committee

• SPIL Sustainability Committee

• USI Sustainability Committee