Sustainability-Linked Bond
A Sustainability-Linked Bond (SLB) is a bond whose financial terms — typically the coupon rate — are tied to the issuer's achievement of pre-defined sustainability performance targets, rather than to a specific use of proceeds.
Unlike green bonds, sustainability-linked bonds are general-purpose instruments. The issuer can use the proceeds for any corporate purpose. What makes them distinct is the penalty mechanism: if the company fails to meet its stated sustainability key performance indicators (KPIs) by a specified observation date, the coupon steps up — typically by 25 basis points — for the remaining life of the bond.
Common KPIs include reductions in Scope 1 and Scope 2 greenhouse gas emissions, increases in renewable energy usage as a percentage of total consumption, gender diversity targets at board or executive level, and reductions in fresh-water withdrawal intensity. Ambitious target-setting is essential to credibility; SLBs where the KPI target is easily achieved regardless of any operational changes have drawn criticism as sustainability-washing.
The ICMA Sustainability-Linked Bond Principles, first published in 2020, outline five core components: KPI selection, sustainability performance target (SPT) calibration, bond characteristics, reporting, and verification. Independent verifiers assess whether the issuer has met its targets at the observation date.
From an investor perspective, SLBs offer broader sector diversification than use-of-proceeds green bonds, since companies in hard-to-abate sectors like steel, cement, and chemicals can issue SLBs tied to decarbonization commitments without ring-fencing capital. The step-up coupon theoretically incentivizes management to meet targets, though critics note that the financial penalty is often small relative to the reputational benefit of meeting the KPI.
SLBs are a fast-growing segment of the labeled sustainable bond market. Sovereign issuers, including Chile and Uruguay, have issued sustainability-linked sovereign bonds tied to national emissions targets — a notable evolution from corporate-only issuance.