This paper investigates whether the Brazilian corporate debenture market prices a greenium—a reduction in issuers’ borrowing costs driven by ESG labeling—at the time of issuance. Using a BRL?denominated panel of corporate debentures issued between 2015 and 2025, we model issuance?day spreads relative to the contractual indexer (DI, IPCA, or PRE) to directly target primary?market pricing. The empirical strategy employs high?dimensional fixed?effects regressions with Issuer and Indexer×Month effects, two?way clustered standard errors, and comprehensive controls for maturity, size, bond type, sector, rating, convertibility, tax?incentivized status, and same?day issuance intensity, isolating within?issuer and within?regime?month variation in spreads. Results indicate a small but emerging greenium: the baseline specification yields a negative coefficient of approximately –18 basis points, robust in sign though sensitive to model granularity and more pronounced after 2019. No consistent differences arise across indexers. Overall, ESG labeling is associated with modest yet economically relevant issuance?day spread reductions.
