The Central Bank of Brunei Darussalam, working with the Sustainable Finance Institute Asia, hosted an ASEAN Taxonomy Board (ATB) meeting and a follow-on webinar focused on the ASEAN Taxonomy for Sustainable Finance. Discussions centred on progress in developing Version 4, intended to expand the taxonomy’s coverage, and on practical use and recent developments following the finalisation of Version 3 on 20 December 2024. The ATB meeting on 29 April 2025 brought together board members from ASEAN financial authorities and sectoral regulators, with participation from the Asian Development Bank and Sustainable Finance Institute Asia. In the webinar keynote, ATB Chair Awang Mardini bin Haji Eddie highlighted interoperability and alignment as core design principles, including the ability for ASEAN Member States to map national taxonomies to either the Foundation Framework or Plus Standard. He also noted that Version 3 has been supplemented with additional Foundation Framework use cases for small and medium-sized enterprises and an accompanying frequently asked questions document, while webinar sessions covered implementation use cases and alignment of national taxonomy initiatives in Indonesia, the Philippines and Thailand with the ASEAN Taxonomy.