Southeast Asia’s transition to a low-carbon economy hinges on one persistent constraint – capital. The Asian Development Bank (ADB) estimates that clean power generation and grid upgrades alone will require $6 trillion in investment globally between 2023 and 2050. For a region where nearly 40 per cent of the population lives in high-tide risk zones and roughly three-quarters of GDP is tied directly or indirectly to natural capital – agriculture, fisheries and tourism – the financing challenge is inseparable from the climate resilience challenge.
Against this backdrop, ADB’s Green, Social, Sustainable, and Other Labeled [GSS+] Bonds Initiative has been a significant initiative towards working to deepen Southeast Asia’s sustainable debt markets. The programme is jointly implemented by the ASEAN Catalytic Green Finance Facility and the ASEAN+3 Asian Bond Markets Initiative, and provides advisory and hands-on support to national and subnational governments, state-owned enterprises, and financial and non-financial institutions looking to issue green, social, sustainability, sustainability-linked, transition or other labelled bonds.
A recent report, “GSS+ Bonds Initiative: Scaling Sustainable Finance in Southeast Asia”, by ADB examines how Southeast Asia can learn from best practices and mobilise capital on a large scale. The report focuses specifically on the progress under the initiative and the key steps required to develop a more mature financing ecosystem.
The adaptation financing gap
Of all climate finance currently flowing into Southeast Asia, only 12 per cent is directed towards adaptation, against 84 per cent for mitigation. This imbalance is part of the rationale for the GSS+ Bonds Initiative’s broader bond taxonomy – spanning social bonds, sustainability bonds, sustainability-linked bonds (SLBs) and transition bonds – rather than a narrow focus on renewable energy project finance alone.
Since 2020, the initiative has supported four activity pillars: structuring signature GSS+ transactions, strengthening the enabling ecosystem, building talent pools, and developing in-house expertise among regional issuers and regulators. The headline numbers reflect that reach: $5 billion in sustainable bonds mobilised since 2020, a further $15 billion in follow-on issuances unlocked as first-time issuers returned to the market, support for 17 award-winning sustainable finance instruments, backing for four local verifiers and contributions to new regulations.
Mapping the market’s progress and footprint across regions
In the past five years, issuances have been dense, most originating in Thailand but increasingly spreading across Cambodia, Indonesia and the Philippines.
Thailand’s Public Debt Management Office issued ASEAN’s first sovereign sustainability bond in August 2020, worth $964 million, and followed in 2023 with Asia’s first sovereign SLB – the third globally – at $880 million. The National Housing Authority issued Thailand’s first social bond ($200 million) in September 2020, while the Government Savings Bank placed a $295 million social bond in 2022.
Corporate and sector firsts followed in quick succession. The Central Pattana issued Thailand’s first real estate and retail sector SLB ($235 million) in 2023, the Provincial Electricity Authority issued Thailand’s first sustainability bond from a state utility ($30 million), and Precious Shipping issued the first SLB by a shipping company anywhere in Asia and the Pacific ($40 million). The WHA Corporation’s 2023 issuance was the first SLB structured under the ASEAN SLB Standards.
Beyond Thailand, Cambodia’s Golden Tree issued the country’s first green bond in December 2022, worth just $1.3 million but symbolically significant for a nascent market. Indonesia’s PT Sarana Multigriya Finansial issued the country’s first social bond and social sukuk (Islamic bond) in 2023, raising $32.4 million and $13 million respectively. In the Philippines, the ASA Philippines Foundation issued the country’s first gender-linked social bond ($90 million) in 2023, and the Asialink Group’s 2025 social bond built on a $70 million raise supporting underserved micro, small and medium enterprises (MSMEs).
Key issuances and best practices
Three transactions stand out as the best practices in the region. The Thai Union Group’s blue and green finance framework – aligned with the Thailand Taxonomy for Aquaculture – supported ADB’s first private sector blue loan in the country, backing sustainable aquaculture, resilient supply chains and financial literacy programmes for farmers. The group followed its $150 million blue loan in May 2025 with a $60 million blue bond in September 2025, marking the first blue bond in Thailand’s aquaculture sector.
The Electricity Generating Authority of Thailand (EGAT) issued the country’s first SLB from a state-owned enterprise, targeting a 30 per cent reduction in Scope 1 and 2 greenhouse gas emissions by 2030 against a 2021 baseline. EGAT’s Deputy Governor for Finance and Accounting, Somchit Dansriprasert, credited ADB’s technical assistance with helping the utility establish credible key performance indicators and financing targets, noting that the support strengthened both market access and internal institutional capacity.
The Asialink Group’s 2025 social bond was supported by the Credit Guarantee and Investment Facility’s first Philippine peso guarantee since 2018 – and its largest peso transaction to date – channelling financing towards MSMEs across the Philippines, including underserved segments.
Building an enabling ecosystem
Beyond individual transactions, the GSS+ Bonds Initiative has invested in market infrastructure. It provided advisory support to help financial and non-financial issuers apply ASEAN and national sustainable finance taxonomies, including end-to-end assistance in developing the Thailand taxonomy itself, from policy design through implementation. The initiative also supported Thailand’s adoption of International Sustainability Standards Board (ISSB) disclosure standards, drawing on local practitioner insights and peer experience from other markets.
The GSS+ Bonds Initiative had been central to strengthening the Philippines’ sustainable finance regulatory framework and capital market ecosystem. Moreover, the initiative’s advisory work has translated into tangible outcomes: 7.64 million cubic metres of water reclaimed, 17,296 metric tonnes of waste diverted from landfills, 521 EV charging stations installed, 70,582 zero-emission vehicles registered, and ₱5 billion allocated towards improving conditions for low-income women.
The way forward
ADB has flagged five priority areas for the initiative going forward: sustainability-linked and transition finance, nature and biodiversity finance, subnational government finance, sustainability disclosure and regional dialogue to support local verifiers. With adaptation finance still lagging far behind mitigation spending, and with subnational and nature-linked instruments largely untested in the region, the next phase of the GSS+ Bonds Initiative is likely to test how far ASEAN’s labelled bond markets can extend beyond sovereign and large corporate issuers towards more distributed, resilience-focused financing.
The Southeast Asian experience offers a working template for India’s renewable energy and infrastructure financing community – multilateral advisory support paired with taxonomy development and verifier capacity-building can meaningfully de-risk first-time issuances and catalyse repeat market access, a lesson with direct relevance to India as its own green and SLB market continues to mature.
