From Digital Finance to Sustainability: Revisiting the Greenium in Modern Bond Markets
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The premise of sustainable finance is elegant: if investors truly care about the environment, they should be willing to accept slightly lower returns to fund it. In bond markets, that willingness has a name — the greenium, the yield discount a green bond enjoys over an otherwise identical conventional one. For years it was one of the clearest pieces of evidence that markets price sustainability at all. Our report asks whether it still holds.
Our report, From Digital Finance to Sustainability: Revisiting the Greenium in Modern Bond Markets, tests the question empirically rather than rhetorically. We build a matched-pair dataset — 100 pairs across 17 EUR issuers, each green bond paired with a conventional bond from the same issuer at the closest maturity — precisely to isolate the green label from everything else that moves a yield: credit quality, duration, currency, and the macro rate environment. We then run a regression controlling for maturity, rating, and coupon, and stress-test the result with subsample splits, alternative specifications, and time fixed effects.
The finding is a quiet one, and that is the point. Across the full sample, green bonds yield fractionally more than their conventional twins — a mean spread of +1.88 basis points, statistically indistinguishable from zero. The regression agrees, at +1.75 bps. There is no detectable greenium here. But the subsamples tell a subtler story: non-financial corporates show the expected negative spread (−8 bps), while financial and covered-bond issuers — which dominate our sample — drift positive (+6 bps). The direction matches the literature; the magnitude is simply too small, and the samples too thin, to reach significance.
What emerges is not a refutation of the greenium but a portrait of its compression. The scarcity premium that sustained negative yield differentials between 2016 and 2021 has largely closed as green bond supply expanded to meet ESG-driven demand. Green bonds today price roughly in line with conventional ones, and the case for issuing them rests increasingly on non-financial grounds — investor base, reputation, and alignment with frameworks like the EU Taxonomy. The signal that ESG once moved prices is real; it has just grown faint.
The Bocconi Students Fintech Society chose the greenium as the focus of this report because it is the cleanest test of a deeper claim: that markets price sustainability preferences at all. The honest answer is that they do — but conditionally and dynamically. Whether the premium re-emerges depends less on investor sentiment than on the quality of the frameworks governing what counts as green in the first place.
Research Report
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Published in July 2026
Project Team
Team Leader: Julien Dietrich
Authors: Luigi Marsero, Subhadeep Dutta , Loukas Iatrou , Adam El Maatoui, Pablo Gadrey
Association Board :
Neil Maaouni (President & Head of Data Analysis), Mathilde Castagine (Vice President & Head of Events), Guillaume Abaz (Senior Advisor to the board), Andrea Botero (Head of M&A and VC), Antonina Bojanowska (Head of Generalist), Noé Wierzba (Head of Operations), Lucas Médina (Head of Corporate Analysis) , Alexandra Minca (Head of Communication)