YUIDEA Inc. (Headquarters: Minato-ku, Tokyo; President and CEO: Kazuhiro Hosoya; hereinafter "YUIDEA") and DEPART INC. (Headquarters: Minato-ku, Tokyo; President and CEO: Takayuki Higashi; hereinafter "DEPART"), companies that support corporate sustainability communication, have released a "3-Part Quantitative Research Report" to promote sustainability information disclosure and management for fiscal year 2026. These reports investigate the disclosure status of highly-rated domestic companies in ESG. They are designed to help disclosure managers solve challenges they face, from responding to institutionalized disclosure standards to the latest website strategies. ■ Background and Objectives Fiscal year 2026 marks a significant increase in the quality of disclosure required from companies, including the institutionalization of standards by the Sustainability Standards Board of Japan (SSBJ), response to double materiality, and advancement of human capital disclosure. Consequently, sustainability initiatives are being undertaken across various internal departments, revealing the challenge of internal penetration in addition to information disclosure. YUIDEA and DEPART have conducted quantitative research utilizing their long-standing consulting experience and specialized knowledge to support corporate sustainability information disclosure. Companies can compare their own information disclosure and sustainability promotion status with the trends of leading domestic companies. ■ Target Companies for Research To provide reference for a wider range of companies, the research targeted 50 leading domestic companies highly rated by major ESG rating agencies FTSE, MSCI, and S&P Global. (As of the end of September 2025). ■ Overview of the 3-Part Research Report [Part 1] Survey on Disclosure Status of Key Sustainability Themes for FY2026 (Sustainability Communicate) This report analyzes the sustainability reports and integrated reports of 50 leading companies, summarizing the la