Sustainable Investing’s Midlife Crisis: What Comes After the ESG Boom?

As southern Europe swelters under a record-breaking summer heatwave, the signs of climate risk are no longer theoretical – they are blisteringly real.

From scorched vineyards in France to shrinking reservoirs in Spain, the environmental urgency that once fuelled the ESG boom is now playing out in real time. Yet, just as the need for sustainable finance intensifies, the narrative around it is entering a period of growing ambiguity and fatigue.

The past 18 months have tested the resilience of ESG and Sustainable Investing. Once the darling of capital flows and policy frameworks, the sector has recently faced intense scrutiny over performance, transparency, and political pushback. Still, the long-term trajectory remains intact. The real question now is how the market evolves in a world where visibility is no longer a guarantee of credibility.

A Bipolar Regulatory World

The divergence in regulatory approaches between the US and Europe is sharpening.

Across the Atlantic, the re-emergence of Trump-era narratives has led to a chilling effect on ESG adoption – The US exit from the Paris Agreement, for the second time, – is symbolically and practically significant.

Meanwhile, Europe is scaling back some of its ambitions through the Omnibus Package, which could limit mandatory reporting under  Corporate Sustainability Reporting Directive (CSRD) and serve to increase data fragmentation.

However, despite slower progress in some areas, product-level regulations in the EU continue to move forward. The ESMA guidelines on fund names incorporating ESG or sustainability-related terms came fully into effect on 21 May 2025. These require that at least 80% of a fund’s assets promote ESG characteristics – and even stricter thresholds apply when sustainability terms are used.

Greenhushing

Faced with reputational risk and high compliance costs, asset managers are increasingly opting for discretion.

Greenhushing – the deliberate under-reporting of sustainability practices – has quietly replaced greenwashing as the industry’s dominant defensive tactic; a trend that only reflects the growing complexity of navigating global rules and the risk of regulatory misalignment, particularly for firms with a transatlantic footprint.

UK vs EU: Diverging but Complementary Paths

In the UK, Sustainability Disclosure Requirements (SDR) are widely seen as more functional and investor-focused than the EU’s Article 6/8/9 SFDR framework.

With the FCA introducing sustainability labels such as “Sustainability Focus” and “Sustainability Improvers,” many hope the EU’s upcoming Q4 SFDR review will align more closely with the UK model. Indeed, the Platform on Sustainable Finance has already proposed a new categorisation system mirroring SDR’s logic – grouping funds into “Sustainable,” “Transition,” and “ESG Collection” categories.

A more unified framework would undoubtedly be welcomed by asset managers. As of now, discrepancies between SFDR and CSRD risk distorting data quality and investor comparability – especially as the Omnibus Package excludes over 80% of previously covered firms from mandatory disclosure.

Overall, fund names are seen to strongly influence, particularly retail, investor decisions and this has been a positive step in combatting greenwashing with the previous 6-9 months seeing widespread changes across the market.

Sustainable Bonds: A Market Reinventing Itself

Despite the ESG backlash, Green, Social, and Sustainability Linked (GSS) bonds are set for another record year, with over $1 trillion in issuance projected for 2025.

Key themes include the refinancing of maturing debt, the critical moment for sustainability-linked bonds, and the implementation of the EU Green Bond Standard (EuGBS).

With new fund naming guidelines applying to GSS funds as well, ESMA now requires these products to meet Paris-Aligned Benchmark criteria – a move that has elevated standards but also narrowed the investable universe.

Future

If last year was about damage control, the next phase is about recalibration. Regulatory frameworks are maturing, investor scrutiny is intensifying, and the political context remains volatile.

Yet structural drivers – from climate change to biodiversity loss – remain as urgent as ever.

In a world where silence can be as misleading as exaggeration, sustainable finance must now prove it can speak with clarity, evidence and impact.

Investors should remain vigilant, as determining the true ESG and sustainability credentials of a fund requires thorough due diligence—there are no shortcuts.

GSS Bonds Market Trends Report, July 2025, Summer Edition

MainStreet Partners’ July 2025 GSS Bonds Market Trends Report shows a 13% year-on-year drop in global Green, Social, and Sustainability (GSS) bond issuance in the first half of 2025, down to $495 billion. Still, Q2 issuance held steady at $250 billion, matching the same quarter last year.

Market sentiment remained cautious amid inflation, trade uncertainty, and geopolitical tension. Yet Green Bonds stayed dominant, especially in the UK, where issuance rose by 10% to $14.7 billion. Financial institutions led the UK market, accounting for 64% of issuances, nearly double the global average.

Sustainability and Social Bond volumes held firm at $131 billion and $82 billion, respectively. However, Sustainability-Linked Bonds saw their weakest first-half on record, at just $421 million.






    GSS Bonds Market Trends Report, May 2025

    Europe Dominates and Middle East Emerges as New GSS Bond Powerhouse despite US lowest global issuance since 2017

    In a year marked by regulatory uncertainty and geopolitical turbulence, GSS bond issuances fell 25% YoY, with US GSS bond issuance reaching its lowest level in Q1 2025 since 2017.

    However, Green Bonds continue to be the cornerstone of sustainable finance, according to MainStreet Partners’ latest report on market trends (GSS Bonds Market Trends Report).

    Despite a global contraction in volumes, green bonds remain the most credible route for investors seeking transparency, impact, and regulatory alignment.






      2025 ESG and Sustainability Barometer

      The status of ESG and Sustainability integration in the UK and European fund markets

      The 2025 ESG and Sustainability Barometer report, which analyses over 9,500 investment strategies managed by more than 460 asset managers, evaluates key ESG and Sustainability-related trends in the European and UK fund markets. It also highlights a clear downward trend in asset manager ratings across each Sustainable Finance Disclosure Regulation (SFDR) classification and non-EU ratings.

      The findings come at a time when sustainability standards and expectations have increased, alongside a pullback of several asset managers from key initiatives like the Net Zero Asset Managers initiative (NZAM) and Climate Action 100+ (CA100+), as well as a general reluctance to discuss ESG and Sustainability in the US.

      MainStreet Partners’ research found that 13% of funds have failed its regulatory adherence assessment – which considers the relevant naming convention of the specific strategy together with the consistency of documentation, ensuring it is clear, not misleading, and uses fitting and targeted language.

      Nearly a quarter (23%) of all Article 8 funds remain at risk of greenwashing. However, the proportion of Article 9 funds that have a greenwashing risk has reduced over time, now sitting at 3%.






        GSS Bonds Market Trends Report, February 2025

        2024 Green, Social, and Sustainability (GSS) Bond Issuance hit almost $1trn – highest annual figure in three years

        The Green, Social, and Sustainability (GSS) Bond market reached its highest point in three years – with issuances hitting just under one trillion dollars ($910bn) in 2024, according to the latest quarterly GSS report by ESG, sustainability and impact data provider MainStreet Partners.

        Social bond issuances saw the biggest increase in 2024 hitting $251bn (2023: $159bn), while sustainability bond issuance suffered the biggest drop to $152bn (2023: $203bn). Transition Bonds also saw something of a revival, displaying a significant growth in activity in 2024, particularly led by Japanese issuers.

        The report also navigates the effect of ESMA’s new Paris Aligned Benchmark (PAB) and Climate Transition Benchmark (CTB) look-through approaches, where the compliance analysis is more focused on the Use of Proceeds rather than on the issuer itself.

        By analysing the projects financed by each of the 5,000 bonds in its database, MainStreet Partners finds that this new regulation is highly relevant for Article 9 fund managers as they should start re-shaping their portfolios in advance, to avoid rapid adjustments concerning GSS Bonds to retain their themed-fund names.






          ESG Risk

          Regulatory Data

          Manage ESG risk with ESG Ratings and analysis, based on robust proprietary methodologies across Equities, Funds, ETFs, Fixed Income and labeled Fixed Income instruments.

          Read more: ESG Risk

          Unique ESG Ratings

          1. Equity and corporate Bond ratings
            Our corporate ESG ratings have been developed to offer an accountable solution for professional investors to navigate the ESG resilience of over 8,000 corporate issuers.
            Our proprietary model uses 200+ metrics to determine each investee company’s performance on the material Environmental, Social and Governance factors, taking double materiality into account.
          1. Funds, ETFs and Index ratings
            Our Fund ratings are industry-renowned, conducting a thorough ESG and Sustainability due-diligence assessment of over 90,000 Funds, ETFs, and Index Funds.
            MainStreet Partners’ unique methodology involves a 3-pillar approach, examining
            01 The overall asset management firm
            02 The fund’s strategy
            03 The underlying portfolio.

          What sets us apart?

          • This holistic approach transcends typical fund ESG ratings, giving insight into how sustainability of a fund is integrated from the Asset Management level through to portfolio manager strategy and investment decision making.
          • We’ve developed a 85+ factor-based scorecard that meticulously evaluates each fund.
          • MainStreet conducts high-level engagement with third-party fund managers, ensuring a deeper understanding of their sustainability profile and any greenwashing risks.

          Regulatory Data

          Regulatory Data

          In a world of ever-evolving sustainability regulation, ESGeverything simplifies alignment of your investment strategies and periodic reporting needs, with comprehensive, all-in-one solutions.

          SFDR Principle Adverse Impact (PAI) Indicators; Sustainable Investment; MiFID II; EU Taxonomy; UK SDR

          SFDR Principle Adverse Impact (PAI) Indicators

          Principle Adverse Impact Indicators (PAIs) are a set of sustainability metrics that financial market participants are required to disclose periodically, under EU’s SFDR.

          How does ESGeverything help you?

          • Access all 16 mandatory PAI metrics across a large database of Equities, Corporate Bonds, Government & Supranational Bonds and Funds & ETFs.
          • Leverage unique PAI scores for simple and effective consideration of PAI within ex-ante investment decision making.
          • Build Do No Significant Harm frameworks in the context of defining Sustainable Investments.
          • Produce quality entity-level and portfolio-level PAI reports in line with SFDR disclosure requirements.

          MiFID II

          With one of the largest collections of EET data across over 400+ Asset Managers, we enable FMPs to easily and efficiently align product offerings to client sustainability preferences.

          EU Taxonomy

          Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo.

          Identify the percentage eligibility and alignment of companies to the EU Taxonomy based on:

          1. Turnover – in monetary value and as a percentage of the company’s total;
          2. CapEx – in monetary value and as a percentage of the company’s total;
          3. OpEx – in monetary value and as a percentage of the company’s total (if relevant).

          Through advanced AI and machine learning technology, we extract this data directly from company reports, saving you valuable research time as disclosure rates evolve.

          • Data Consistency: Standardized data across corporate entities ensures consistent and reliable comparisons.
          • Sustainable Investing Alignment: Identify companies strategically positioned for the transition to a sustainable economy.
          • Regulatory Compliance: Meet your sustainability disclosure obligations with confidence.

          UK SDR

          MainStreet Partners has a very unique and robust approach to the ESG rating of Funds & ETFs and so over 6 years of experience in providing ESG focused due-diligence assessments. Our methodology entails an in-depth analysis of the:

           

            1. Asset Management firm

            1. The Fund’s Strategy

            1. Regulatory Adherence to SDR Anti-greenwashing rules

            1. Fund Portfolio
              MainStreet Partners has a dedicated Sustainable Fund Research team that conduct an independent factor based assessment on a large scope of Funds, with a proven track record and expertise in ESG.

              How does this help UK FMPs?

           

            • Assess a fund’s sustainability objectives, the evidence-based absolute measure of sustainability and that the underlying assets do not conflict this sustainability objective (as required by the FCA)

            • Identify potential greenwashing risk

            • Identify weak and strong sustainability strategies enabling investors to mitigate ESG risk, and cease sustainable investment opportunities.

          GSS Bonds Market Trends, Spring Edition 2024


          Sovereigns leading the charge in the global Sustainability Agenda

          The report finds that Sovereign GSS Bond issuance reached a record-breaking USD 160 billion of issuance, which accounted for almost one-third (31%) of Green Bonds issued last year.

          The top beneficiary of this investment (accounting for 43% of the use of proceeds) was Clean Transportation, perhaps surprisingly receiving three-times the investment awarded to Renewable Energy projects by other, non-Sovereign GSS Bond market issuers.

          While Sovereign bonds tend to tackle a greater variety of project types, including in several “underfunded” categories, their comparatively minor focus on Renewable Energy leads to a lower average Alignment with the European Taxonomy;

          The difference stems mostly from the broader programs financed by governments, often providing less evidence that can be used to analyze their Taxonomy Alignment.






            2024 ESG Barometer

            The status and development of ESG Integration and Sustainability in the Fund Market

            This comprehensive annual report is the result of analysis conducted by MainStreet Partners’ dedicated Fund Research team, drawing on its proprietary ESG database of more than 7,700 funds/ETFs and over 83,000 individual ISINs, covering more than 350 Asset Managers with AUM totalling more than €10 trillion.

            The 2024 ESG Barometer identifies trends in the European and UK funds market, highlights the value of the European ESG Template (EET) by identifying fund sector-specific sustainability trends, the relationships between ESG factors as well as identifying the leaders and laggards in terms of disclosures.

            It also provides a synopsis of ESG regulatory developments and specialised research articles such as developments around ESG integration within private assets, a thematic deep dive into supply chains underlining the challenging reality of global consumption and highlights on how asset managers can look beyond company operational sustainability and understand how companies play into global ecosystems to identify companies with business models that challenge the status quo.






              GSS Bonds Market Trends Report, Q3 2023

              Climate Change Adaptation is currently under-funded in the Green Bonds Sector.

              This quarterly report highlights key drivers for the allocation to Use of Proceeds and how these impact investors