Blue finance is a rapidly growing area of sustainable finance that focuses on directing investment towards projects, infrastructure and initiatives that support healthy marine and freshwater environments and a sustainable "blue economy."
With the issuance of the blue repo by Banco do Brasil earlier this year and an increasing number of blue bonds issued in recent months - including the first blue bond for a water utility in Europe for Saur and the Blue Transition Bond fund by Fidelity last year - 2025 marks a significant milestone in the growth of blue finance.
In a dedicated article, Rebecca Smith, Leisa de Souza and Thatyanne Gasparotto from Natixis CIB Green & Sustainable Hub examine the development of Blue Finance, the way to define it and the increasing interest it is raising from investors.
Water issues overlap not only with biodiversity but also climate adaptation, as water supply and wastewater treatment investments are directly impacted by droughts, heavier rainfall patterns as well as increased frequency of extreme weather events.
Rebecca Smith
The Growth of Blue Bonds
In 2023, a total of 16 labeled blue bonds were issued, raising $4.79 billion. This was followed by 22 issuances in 2024, amounting to $3.22 billion. Although the total amount raised in 2024 was lower, the increase in the number of issuances indicates a growing acceptance of this financial format among issuers.
The trend continued into 2025, reflecting a robust interest both from issuers and investors in blue finance.
Saur's blue bond and Banco do Brasil's blue repo represent a milestone in the evolution of the blue market, as these transactions extend opportunities for blue finance beyond ocean and marine protection.
Thatyanne Gasparotto
A Holistic Approach to the Water Cycle
Blue bonds are a subset of green bonds and, as such, are aligned to the International Capital Market Association (ICMA) Green Bond Principles. However, monitoring blue debt remains complex due to the variety of labels (blue, water, etc.) left to the discretion of the issuer and the heterogeneous market orientations.
The ICMA has published guidance focusing on marine resources and coastal ecosystems, whereas other approaches, such as the guidance from the International Finance Corporation (IFC), adopt a broader interpretation that includes freshwater management and wastewater treatment.
Natixis CIB Green & Sustainable Hub advocates for a consolidated approach that aligns with the water cycle, encompassing the interrelationships between freshwater bodies and marine ecosystems. This approach recognizes that runoff can both nourish oceans with nutrients and organic matter and potentially harm marine ecosystems.
This was the reason why in the Equity Index “Euronext Water and Ocean Europe 40 EWD5” designed by Natixis CIB, the eligibility criteria target companies contributing both to supplying, treating, preserving, optimizing the freshwater resource but also protecting oceans.
The blue label represents a commitment to water-focused initiatives, with recent guidance establishing clear eligibility criteria for what activities can be funded.
Leisa de Souza
A Broader Trend in Sustainable Finance
2025 opened the door to a push in broadening the concept of blue finance to other financial instruments beyond bonds and which now includes repos, such as the $95 million blue repo issued by Banco do Brasil with Natixis CIB in March 2025, aimed at financing its portfolio in water and sanitation. This highlights the evolving nature of blue finance and its potential to encompass various financial instruments.
The rise of blue finance is a vital step in integrating water-related sustainability into the financial landscape and is indicative of a broader trend in sustainable finance. As themes related to the preservation of natural resources, biodiversity, and the environment gain prominence, blue finance is poised to play a crucial role in addressing global challenges related to water and marine conservation. This growing awareness among investors underscores a commitment to environmental preservation and responsible investment practices.
