European banks' green bonds barely dent asset base, research finds

Europe's largest banks talk a good game on green bonds. The numbers tell a different story. Outstanding green bonds represent less than 1% of total assets, on average, across the 47 biggest banks on the continent, according to research published on 3 September by the Institute for Energy Economics and Financial Analysis (IEEFA). That figure alone would be unremarkable if it described a niche product still finding its feet. But most of these banks have had green bond frameworks in place for years. The frameworks exist. The volume does not.

A marginal share of a vast balance sheet

The IEEFA analysis covers the 47 largest European banks by asset size. Together they hold trillions of euros in assets, spanning mortgages, corporate loans, sovereign debt and trading books. Against that backdrop, green bond issuance is a rounding error. Kevin Leung, the report's author and a sustainable finance analyst at IEEFA, put the point bluntly: "Green bond issuance remains too small to materially shift European banks' asset allocation."

This matters because banks are the primary conduit through which capital reaches the real economy in Europe. Unlike the United States, where capital markets dominate corporate funding, European companies still rely heavily on bank lending. If banks are not directing meaningful volumes towards transition-related assets, the transition itself slows. The European Central Bank's own supervisory work on climate-related and environmental risks has repeatedly flagged the gap between banks' stated commitments and their actual portfolios.

Where the money actually goes

The headline shortfall in volume is only part of the problem. The composition of green bond proceeds also raises questions about what these instruments are actually funding.

Renewable energy projects account for roughly 20% of the proceeds allocated by European banks' green bonds, according to IEEFA's findings. Yet that same 20% share is responsible for approximately 90% of the avoided emissions that banks report from their green bond programmes. In other words, the category that does the heavy lifting on decarbonisation receives a minority of the cash.

Green buildings, by contrast, absorb around 70% of proceeds but generate just 3% of reported avoided emissions. The disparity is striking. It suggests that banks' green bond programmes are dominated by a sector where the climate impact per euro spent is relatively modest, while the sector with the highest decarbonisation return on capital is comparatively underfunded.

Leung argued that "this composition of allocations does not squarely address Europe's clean transition and resilience needs." He called for banks to direct funding towards "a well-represented set of transition-critical assets, which have low climate risk exposure."

Why buildings dominate

There are straightforward commercial reasons why green buildings soak up so much of the proceeds. Mortgage lending is the core business of many large European banks. In Germany, France and the Netherlands, residential and commercial property loans account for a substantial share of total lending. Reclassifying a portion of that existing mortgage book as green, or issuing a green bond to fund energy-efficient mortgages, is far simpler than developing new lending products for wind farms or solar parks.

Property-related green bonds also benefit from established certification standards and relatively low-risk profiles. Banks understand buildings. They have collateral, they have valuation models, and they have decades of performance data. Renewable energy projects, by contrast, involve construction risk, permitting uncertainty and longer payback periods. From a risk-adjusted return perspective, a green mortgage portfolio looks more attractive to a bank's treasury than a portfolio of project finance loans to wind developers.

The problem is that what is convenient for bank balance sheets is not necessarily what Europe needs for its energy transition. The European Commission's own energy projections make clear that scaling up renewable generation capacity is the single most capital-intensive element of achieving net zero by 2050.

Frameworks without teeth

Nearly all of the 47 banks in the IEEFA sample have published green bond frameworks. These documents set out the eligibility criteria for projects that can be funded by green bond proceeds. They are typically reviewed by external auditors and aligned with voluntary standards such as the International Capital Market Association's Green Bond Principles.

The existence of a framework, however, does not guarantee ambition. A framework can be broad enough to include energy-efficient building renovations alongside renewable energy, and banks are free to allocate proceeds between those categories as they see fit. The IEEFA findings suggest that most banks default towards the categories that fit most naturally within their existing business models, rather than using green bonds to finance new types of lending that would push their portfolios in a genuinely different direction.

Leung's diagnosis was direct: "Green bond programmes are held back by banks' business-as-usual lending to high-emitting assets and a limited pipeline of green projects." The implication is that banks continue to lend to carbon-intensive sectors through their conventional books while using green bonds to rebrand a narrow slice of their activity.

Regulatory pressure, limited results

European policymakers have spent considerable effort building the architecture for sustainable finance. The EU Taxonomy classifies which economic activities qualify as environmentally sustainable. The European Green Bond Standard, which entered application in late 2024, sets more stringent requirements for bonds that carry the EU label. The European Banking Authority has published guidelines on how banks should manage environmental risks.

These measures were supposed to channel capital towards transition activities. The IEEFA data suggests that, so far, the effect on bank balance sheets has been marginal. One reason is that most green bonds issued by European banks predate the EU Green Bond Standard and were issued under the older, looser ICMA framework. Another is that the taxonomy covers a wide range of activities, including building renovations, which means that compliance with the taxonomy does not automatically mean alignment with the most impactful decarbonisation investments.

Banks also face a genuine constraint on the supply side. The pipeline of investable green projects in Europe is not unlimited. Permitting delays for renewable energy installations, grid connection bottlenecks and planning restrictions in several member states mean that even banks willing to lend more to clean energy may struggle to find enough bankable projects.

What IEEFA wants banks to do differently

The report's central recommendation is that banks should stop treating green bonds as a standalone product and start integrating them into broader transition strategies. Specifically, IEEFA says banks should link green bond programmes explicitly to their sustainable finance targets, their transition plans and their risk management frameworks.

This would mean, in practice, that a bank setting a target to reduce the carbon intensity of its loan book would use green bond proceeds to fund the assets most likely to deliver that reduction, rather than the assets that are easiest to classify as green. It would also mean that green bond programmes would be judged not just by the volume of issuance but by whether the proceeds are shifting the bank's overall asset allocation away from high-emitting sectors.

Leung described the current state of play as a missed opportunity. "European banks have the opportunity to move from issuing green bonds as a mature market practice to using them as a strategic instrument for financing the assets Europe needs for its climate and energy security agenda," he said.

The credibility question

For banks, the risk is not only that green bonds fail to move the needle on decarbonisation. It is also that the gap between their public commitments and their actual allocations erodes credibility with regulators, investors and the wider public. The European Central Bank has already begun incorporating climate risk into its supervisory assessments of banks. If green bond programmes are seen as window dressing rather than a genuine shift in capital allocation, supervisors may conclude that banks are not taking transition risk seriously enough.

Investors, too, are becoming more sophisticated in scrutinising green bond use-of-proceeds reports. A bond that funds energy-efficient mortgages in a sector where banks were already lending may attract less enthusiasm from impact-focused investors than one that finances new wind capacity or grid infrastructure. The market for green bonds is maturing, and with it the expectations placed on issuers.