Climate Bonds Standard: Criteria, Verification, and Reporting

Climate Bonds Standard certification is a voluntary label awarded by the Climate Bonds Standard Board confirming that a bond, loan, or other debt instrument finances projects aligned with the Paris Agreement’s 1.5°C warming limit. To earn it, an issuer must meet sector-specific emissions criteria, engage an approved third-party verifier, pay a certification fee, allocate proceeds to qualifying assets within set deadlines, and submit annual reports for as long as the certification requirements apply. The current release is Version 4.3.¹

What Can Be Certified

Earlier versions of the standard covered only use-of-proceeds bonds and loans, where borrowed money is earmarked for specific green projects. Version 4.0, released in 2023, widened the scope to four categories: use-of-proceeds debt instruments, standalone assets, non-financial corporate entities, and sustainability-linked debt issued by non-financial entities.²

That last category matters. A sustainability-linked bond does not ring-fence proceeds for green projects; its financial terms adjust based on whether the issuer hits company-wide climate targets. Certifying those instruments means the Board now evaluates the credibility of a company’s entire transition plan, not just its project pipeline. The standard also requires issuers to address material Scope 1, 2, and 3 emissions and to set short-, medium-, and long-term targets backed by credible transition plans.²

Which Sectors Have Published Criteria

The Climate Bonds Taxonomy groups eligible activities into sectors, each governed by its own detailed criteria document. If a sector has no published criteria, assets in that space cannot be certified even if they appear environmentally beneficial. As of 2025, published sector criteria cover two dozen categories across the following areas:³

Energy: solar, wind, hydropower, geothermal, bioenergy, marine renewable energy, electrical grids and storage, electrical utilities, and hydrogen
Transport: land transport and shipping
Buildings and industry: buildings, cement, steel, and basic chemicals
Agriculture and land use: agriculture production, alternative proteins, protected agriculture, forestry, and agri-food deforestation-free sourcing
Water and waste: water infrastructure and waste management
Food value chain
Resilience: climate adaptation projects

Each sector document sets quantitative thresholds calibrated to scientific decarbonization pathways. Power generation, for example, must stay under declining grams-of-CO₂-per-kilowatt-hour caps on a defined schedule running through 2045.⁴ Buildings must follow a zero-carbon trajectory, with national building codes and sustainability ratings serving as accepted proxies for top-tier performance in the local market.⁵ A project that qualifies today may not qualify under the same criteria five years from now.

Pre-Issuance: Building the Case

Before any instrument can receive even provisional certification, the issuer has to put several pieces in place.

Internal Systems and Controls

The issuer must document, and disclose to the verifier, the systems used to manage proceeds. Three capabilities are mandatory: tracking proceeds through a sub-account or sub-portfolio, managing unallocated proceeds, and earmarking funds to specific nominated projects and assets. Where ring-fencing is required by the prospectus, proceeds must sit in designated accounts that can only fund the specified projects, with monitored payments.¹

Any proceeds not yet deployed must be held in cash, money-market instruments, or similar liquid short-term positions. The standard explicitly prohibits parking unallocated funds in greenhouse-gas-intensive projects or anything inconsistent with a low-carbon economy.¹

Hiring an Approved Verifier

Every issuer must engage a third-party firm from the Climate Bonds Initiative’s registry of approved verifiers. These are not self-appointed consultants; they are organizations formally vetted by CBI. The current list includes roughly 60 firms, including major accounting networks such as EY, KPMG, and PwC alongside specialized environmental consultancies including DNV, Bureau Veritas, and ERM.⁶ The verifier examines the issuer’s green finance framework, internal controls, and nominated assets, then produces a verification report confirming alignment with the standard.

Verifier fees are negotiable and depend on the size and complexity of the issuance. Available data puts typical costs in the range of roughly $10,000 to $50,000, though those figures date from 2018 research and may be higher now given the expanded scope under Version 4.0.

Submitting the Application and Paying the Fee

Once the green finance framework, the list of eligible projects and assets, and the verification report are complete, the issuer submits the package to the Climate Bonds Standard Board. A certification fee is charged when the label is awarded. The minimum is $2,000 for issuers in developed countries and $1,000 for issuers in developing countries, scaling upward with the size of the issuance.⁷ If the Board finds the application compliant, it grants pre-issuance certification, and the issuer can market the debt as a Certified Climate Bond.

Post-Issuance: The 24-Month Deadline

Pre-issuance certification is provisional. The issuer must allocate the net proceeds to nominated projects and assets within 24 months of issuance. The Board can extend that deadline to five years, or in exceptional cases up to ten years if the nature of the projects justifies it.¹

At the end of the allocation period, the issuer must provide a post-issuance verification report from an approved verifier confirming that 100% of proceeds have been deployed to eligible assets. Until that confirmation lands, annual post-issuance verification reports may be required.¹

Annual Reporting Obligations

Certification is not a one-time stamp. Issuers must submit an annual update report starting 12 to 24 months after the date of issuance and continuing annually until all post-issuance requirements are satisfied. A verification report from an approved verifier can substitute for the update report in any given year. After post-issuance requirements are fulfilled, continued annual reporting is encouraged but not mandatory for most instruments.¹

Some instruments face stricter ongoing duties. Revolving credit facilities, debt financing assets whose eligibility depends on an emissions threshold monitored over time, and instruments backing dynamic asset portfolios (such as green mortgage pools where the underlying properties change) must keep submitting annual update reports until maturity.¹

Programmatic Certification for Repeat Issuers

Issuers planning to bring multiple certified instruments to market from the same pool of eligible projects can use programmatic certification. The first instrument goes through the full process including verification. For each subsequent instrument issued under the program, the issuer submits a completed information form to the Board and receives certification without a fresh standalone verification.¹

Annual verification must begin within 12 to 24 months of the first instrument’s issuance and continue each year that outstanding certified instruments have not yet been covered by a post-issuance verification report. Once the programmatic process is complete, annual verifier engagement is no longer required.¹ For frequent issuers, the upfront verification investment covers the entire program rather than each tranche.

What Happens If Certification Is Lost

If a certified instrument no longer conforms to the standard, the issuer must disclose that fact to the Board within one month of discovering the problem. The Board may suggest corrective actions, and if the issue can be fixed, certification survives. If it cannot, the label is pulled.¹

In cases of alleged breach, the Board can require the issuer to hire a different approved verifier and produce a new verification report within three months. No more than one such report may be requested in any six-month period.¹

Once certification is formally revoked, the issuer must stop using the certification mark, take steps to remove the instrument from any indices or lists that require certification, and inform bondholders, relevant exchanges, and other transaction parties of the status change. Revocation decisions can be appealed through the Climate Bonds Standard Complaints and Appeals Policy.¹

Certification Is Not the Same as a Green Label

Any issuer can call a bond green. There is no law against it, and much of the green bond market grew on self-labeled instruments. Self-labeling relies on investor trust in the issuer’s own claims, and investors’ capacity to independently assess green credentials is limited in fast-moving debt markets.⁸

Climate Bonds certification adds three things self-labeling lacks: independent third-party verification against published scientific thresholds, ongoing reporting obligations enforceable through revocation, and a public registry that lets any investor confirm a bond’s status. The certification relates exclusively to climate attributes. It does not address broader ESG factors or creditworthiness.

1
Climate Bonds Initiative. Climate Bonds Standard Version 4.3
2
Climate Bonds Initiative. Climate Bonds Standard Version 4.0
3
Climate Bonds Initiative. Sector Criteria
4
Climate Bonds Initiative. Electrical Utilities Criteria
5
Climate Bonds Initiative. Buildings – Sector Criteria
6
Climate Bonds Initiative. Approved Verifiers / External Review Providers
7
Climate Bonds Initiative. Certification Fee Policy
8
Climate Bonds Initiative. Climate Bonds Standard Version 3.0