Carbon Credit Provider Due Diligence: Documents Buyers Should Request

On 6 August 2024 the Integrity Council for the Voluntary Carbon Market ruled that eight renewable energy methodologies could not carry its integrity label, having failed its assessment framework on additionality. Those eight covered roughly 236 million unretired credits, around 32 per cent of the voluntary market. In May 2026 the same body approved a renewable energy methodology, VMR0017.

Same project type. Opposite answer. What separates them is a methodology code and a version number, neither of which appears in a sales deck.

That is the whole problem with carbon credit due diligence. Almost everything that determines whether a credit is defensible sits in documents the seller has but does not volunteer, and a buyer who asks for project type, country and price has asked for none of them. Six documents do the work. Request them in writing, before the price conversation, and name each one precisely enough that a vague answer is visibly a vague answer.

Document One: The Registry Record And Serial Number Block

Ask for the registry name, the project identification number, and the serial number range of the specific units being offered to you.

Not the project's total issuance. The block. A serial number range identifies the exact units, which is what lets you confirm they exist, that they are the vintage you were told, and that they have not already been retired or transferred to somebody else. Then look them up yourself in the registry's public view rather than accepting a screenshot.

Two things go wrong here and both are visible from the range. The first is that the seller is offering units from a pool they do not yet hold, which shows up as an inability to name a block at all. The second is that the block has been offered to more than one buyer, which you cannot see directly but which becomes very hard to sustain once a buyer insists on a named range and a transfer into their own registry account.

Verra's registration and issuance process gives the registry the job of generating serial numbers and creating the project and unit records. It does not publish a serial number structure, so do not try to interpret the string. Treat it as a lookup key and use it.

Also ask who holds the units today. A credit sitting in a broker's account three intermediaries deep is a different commercial risk from one sitting with the project proponent, and the registry account name tells you which you are buying.

Document Two: The Methodology, With Its Version Number

Ask for the methodology code, the version applied to this crediting period, and the date that version took effect.

The version number is the part that matters, and the Integrity Council's own record shows why. Its August 2024 decision named specific codes: ACM0002, ACM0006, ACM0018, AM0036, AM0072 and AMS-I.D for grid-connected renewables, AMS-I.L for mini-grids, AMS-I.A for off-grid. Its May 2026 approvals were equally specific, covering VMR0017 for wind, solar, geothermal, small-scale hydro and wave or tidal projects, and ACM0008 for coal mine methane at versions 6 to 8 only, limited to projects that capture and destroy or use the methane, and requiring a named additionality tool and an investment analysis test.

Versions 6 to 8 only. A buyer told "this project uses ACM0008" has been told almost nothing.

So the useful question is not whether a project type has integrity in general. It is which version of which methodology generated these units, and what the relevant assessment body has said about that version. If the seller cannot answer without checking, that is informative; if they answer with the project type instead, ask again.

One more request belongs here. Ask for the project design document and any revisions to it, because the methodology tells you the rules and the design document tells you how the project applied them, including the baseline it chose.

Document Three: The Issuance Record And Verification Report

Ask for the verification report, the name of the validation and verification body, the verification period it covers, and the issuance record showing what was issued against it.

Check the vintage arithmetic. Verra's process states that where a verification period includes more than one calendar year, the registry displays separate vintages for each calendar year. So a single verification covering 2023 and 2024 produces two vintage lines, and a seller describing the whole block as one vintage has either simplified or misread their own record. Either way you want to see which.

The verification body's identity is worth more attention than it usually gets. Ask how many verification cycles that body has performed on this project, and whether it has ever been suspended or had its accreditation restricted by the programme. Accreditation actions are public, and a project whose entire history has been verified by a single body with an enforcement record is a different proposition from one with rotated verifiers.

Then ask for the gap between the verification date and the issuance date, and between issuance and today. Old issuances from long crediting periods under superseded methodology versions are the cheapest credits on the market, and the discount is usually the market pricing in the risk you are being asked to take.

Document Four: The Retirement Record

Ask who will retire the units, in which account, on what date, and what the retirement record will say.

This sounds procedural and it is where a surprising number of arrangements fail. Retirement is what converts a tradable unit into a consumed one, and until it happens the unit can be sold again. Verra's process has the account holder initiate retirement, designate the specific units, and pay a fee, with incremental retirement permitted, so a block can be retired in parts over time. If you are buying a block and the seller retires it in tranches, your claim covers only the tranches already retired.

Here is the detail worth knowing before you draft the contract. The process document says the registry records the details of all unit retirements, but it does not specify that those details include a named beneficiary or a stated reason. So "we will retire these on your behalf" is a contractual promise rather than a registry feature, and the only way to know what the public record will show about you is to look at completed retirements for the same registry and project before you sign.

Ask for a sample retirement record from a previous transaction. If your organisation's name is going to appear nowhere in the registry, you need to know that while you still have leverage over the contract wording.

Document Five: The Non-Permanence Risk Report

For any land-based or storage-based project, ask for the non-permanence risk report and the risk rating it assigned.

That rating is the buffer withholding percentage. Verra's process applies the rating from the verification body's non-permanence risk report to the net reductions and removals in the verification report, and buffers reductions and removals separately. The percentage is project-specific and it lives in that report, not in the methodology and not on the registry page, which is why it has to be requested by name.

The structure of the buffer is worth understanding before you rely on it. Buffer credits are not tradable units, carry no serial numbers, and are not subject to the issuance levy. The pool that underwrites permanence is therefore made of holdings you cannot look up the way you can look up the credits you bought.

Release rules tell you how the programme itself reads the risk. Buffer credits are not released where a project's risk rating increases. Where the rating is unchanged after five years, a 15 per cent time release applies. For geological carbon storage, the first half becomes eligible for release at site closure and the remainder after post-injection site care is complete.

Two questions follow from that. What is this project's current rating, and has it changed since the last verification. A rating that has risen is a signal the programme has already acted on by withholding release, and the buyer should act on it too.

Document Six: Evidence For The Claim You Intend To Make

Decide what you are going to say publicly, then ask for the evidence that supports saying it. In that order, because the claim determines the documents and not the reverse.

The regulatory ground moved this autumn. Directive (EU) 2024/825 on empowering consumers for the green transition had to be transposed by member states by 27 March 2026 and applies from 27 September 2026. The Commission's own material describes it as addressing claims about products' environmental impacts that rely on the offsetting of greenhouse gas emissions, and practitioner readings describe the practical effect as prohibiting carbon neutrality claims based solely on offsetting. Because it is a directive rather than a regulation, the operative text is the national transposition in each market where you make the claim, and that is what your legal team should be reading.

Claims about future environmental performance carry their own evidential burden under the same instrument, reported as requiring clear and objective commitments, a detailed implementation plan, and periodic verification by an independent third party expert. A pledge with no verification arrangement attached is the weakest position available.

Reporting obligations pull in the same direction. ESRS E1-7 requires an undertaking to disclose the amount of emission reductions or removals from mitigation projects outside its value chain that it has financed or intends to finance through any purchase of carbon credits, and states the objective as providing an understanding of the extent and quality of those credits where they support a neutrality claim. Extent and quality both have to come from somewhere, and that somewhere is the five documents above.

Finally, if the seller says the credits are eligible under an international scheme or authorised by the host country, ask for the host country's letter of authorisation. Without it, you cannot rule out that the same tonne is also being counted towards a national target.

The Request, In One Table

Send the list as a numbered request with a deadline, and keep the reply. A seller's written answer dated before purchase is the most useful document in the file, whatever it says.

What To Do If A Document Is Missing

Score the gap by whether you can close it yourself. A serial number block you can verify in a public registry. A methodology version you can look up. A non-permanence risk report you cannot reconstruct, and a host country authorisation you cannot obtain on the seller's behalf.

So treat a missing risk report or authorisation differently from a missing screenshot. The first two are evidence that does not exist outside the seller's file; the last is an administrative delay.

And if the answer to several requests is that the information is commercially confidential, record that as the finding and price it. Confidentiality is a legitimate position for a seller to take. It is also, for a buyer who will have to defend a public claim, an answer.

Position as of 23 October 2026. Programme rules, methodology versions, assessment decisions and buffer release provisions are revised by the bodies that publish them, often without notice, and the Verra provisions cited are from the version of the registration and issuance process read on that date; confirm the current version before relying on any detail. Verra is cited as a worked example because its process documents are public, not as a comparative judgement, and other programmes structure issuance, retirement and buffer pools differently. Integrity Council decisions cited are specific to named methodology codes and versions and do not extend to other versions or project types. Directive (EU) 2024/825 is a directive, so the binding text in any market is the national transposition, which may differ in scope, wording and enforcement; the characterisation of its practical effect on offsetting-based claims reflects practitioner commentary rather than a quoted provision and should be verified against the transposed law. Nothing here is legal, accounting, tax or investment advice, and none of it is a view on whether any particular credit, project or provider is suitable.

Sources

Integrity Council for the Voluntary Carbon Market, Verra, European Commission, ESRS E1, European Financial Reporting Advisory Group

This article is intended for general professional information and does not constitute legal, financial, or investment advice.