Carbon Credit Vintage: Why Older Tonnes Trade at a Discount

A carbon credit is a tonne of carbon dioxide reduced or removed in a specific year. That year, the vintage, now moves price more than almost any other variable. In 2024, credits with a vintage from the last five years sold at a 217 percent premium over older credits, up from a 53 percent premium the year before, according to the Ecosystem Marketplace benchmark report. For a market where total transaction volume fell by a quarter, that is a striking split. It means the same project, the same methodology and the same registry can produce tonnes that trade at very different prices depending on the calendar. Anyone holding, lending against, or trading carbon credits needs to understand why.

Vintage is a maturity date in reverse

In fixed income, time works for the holder: a bond pulls toward par as it approaches maturity. Carbon credits run the other way. A tonne issued for a 2016 reduction loses value every year it sits unretired, and the decay has accelerated. Market analysts have put the average uplift for a newer vintage at roughly 18 percent per year, which compounds into the triple-digit gap that the 2024 data shows.

Three forces drive the discount. The first is methodology drift. Older credits were issued under earlier versions of crediting rules, many of which have since been tightened or withdrawn. A buyer who retires a 2014 avoided-deforestation tonne today is retiring something the current standard might not issue at all. The second is eligibility. Compliance and quasi-compliance programs increasingly set vintage cutoffs. Colombia's carbon tax disallows credits older than five years, and the aviation sector's offsetting scheme restricts eligible vintages to a defined window. Every cutoff removes a class of buyer from the older tonne's demand curve. The third is reputational. Corporate buyers who disclose their retirements have learned that a stack of decade-old credits reads as cheap compliance rather than real procurement, and their auditors and stakeholders read it the same way.

The result is a market with two prices for what is nominally the same unit. The Ecosystem Marketplace data shows 2024 posting the lowest transaction volume since 2018, yet market value sitting at 1.9 times the 2018 level on the strength of buoyant prices for the credits buyers actually want. The spread between the wanted and the unwanted tonne is where the money is.

Source: https://www.forest-trends.org/pressroom/benchmark-report-finds-the-voluntary-carbon-market-in-transition-demand-holding-steady-as-turnover-stabilizes/

The overhang nobody marks

The unretired stock of older credits is large. Industry analysts describe older vintages as a significant portion of the outstanding inventory, much of it held by developers, intermediaries and corporates who bought at prices that no longer clear. That overhang matters for three reasons that are familiar from any other asset class.

It is a balance-sheet problem. A corporate that bought 500,000 tonnes of 2017 vintage at a price appropriate for 2021 now holds an inventory position that is worth a fraction of its cost. Most of those positions are still carried at cost, because there is no widely accepted mark and because the holder has no obligation to find one until retirement or audit forces the question. That is the same valuation lag that plagues other private assets. It makes the position look safer than it is and makes the eventual write-down larger.

It is a liquidity problem. Older tonnes trade in a thinner market with wider bid-ask spreads, because the buyers who can use them are fewer and the sellers are more motivated. Thin markets reward whoever has the best information about which specific serial numbers are eligible for which programs. That information asymmetry is a cost to every participant who lacks it.

It is a collateral problem. Lenders who take carbon credits as security have to haircut for vintage decay in a way they do not for gold or treasuries. A loan secured by 2023 removal credits and a loan secured by 2015 avoidance credits are not the same loan, even if the tonne counts match. The market's earlier analysis of what lenders check before taking carbon credits as collateral applies with extra force here: vintage is a line item in every haircut schedule.

Quality labels are compressing the curve from the top

While older tonnes decay, the newest high-integrity credits are pulling away. The Integrity Council for the Voluntary Carbon Market reported in December 2025 that credits carrying its Core Carbon Principles label command a premium averaging up to 25 percent over other credits, with seven programs and 35 methodologies now approved. Ecosystem Marketplace's 2024 data shows the mechanism in one segment: the average price of landfill gas credits rose 35 percent from the first half of the year to the second after the label was granted, on 3.1 million credits traded, a 149 percent volume increase on 2023. Trade-press analysis of first-quarter 2026 pricing suggests the labelled-credit premium has widened further since.

Source: https://icvcm.org/core-carbon-principles-at-the-heart-of-market-transformation-report/

Put the two trends together and the carbon market now has a steep term structure. Recent, labelled, removal-weighted tonnes sit at the top. Old, unlabelled, avoidance-weighted tonnes sit at the bottom. Everything in between is priced by a combination of registry, methodology version, host-country status and age that no single screen displays. That is a market structure problem, and market structure problems have market structure solutions.

What a dated, verifiable tonne changes

The reason vintage is hard to price is not that the data does not exist. Every registry records the vintage year, methodology version and issuance date against each serial number. The problem is that the data lives in several incompatible registries, is read through PDFs and portals, and is not attached to the unit when it moves between holders. A buyer evaluating a block of credits has to reconstruct the vintage, methodology and eligibility profile by hand, and the seller has every incentive to describe the block in the most favourable terms.

A tonne whose registry state is attached to the unit itself, readable by any counterparty and verifiable against the issuing registry without a phone call, changes that. It does four things.

It makes vintage a displayed attribute rather than a discovered one. Bid-ask spreads narrow when both sides can see the same serial-level data. The 217 percent premium is a real price signal, but today it is realised mostly by participants with the resources to run their own registry reconciliation. A common data layer lets smaller buyers and holders capture the same signal.

It makes the mark defensible. A corporate treasury that holds carbon inventory, or a fund that holds it as an investment, can mark each lot against a vintage-and-label-adjusted reference rather than at cost. That is the shift described in earlier coverage of carbon inventory moving onto the balance sheet as a treasury position. It is also the shift that auditors are starting to demand.

It makes eligibility programmable. If a credit's vintage and methodology are machine-readable, a buyer can filter for program eligibility at the point of trade instead of after settlement. A tonne that cannot be used for the buyer's stated purpose never enters the order.

It makes the overhang tradable. Older vintages are not worthless. There are buyers for whom a 2017 reduction credit is perfectly suitable, including voluntary buyers with no label requirement and some domestic programs with looser cutoffs. The problem has been matching that demand with that supply in a market where neither side can see the other. Transparent serial-level data turns an illiquid overhang into an orderly discount curve, which is what every other asset class with age-dependent value already has.

The broader principle is the one that underpins verifiable data for every real-world asset: a claim that can be independently checked is worth more than a claim that must be taken on trust, and the market pays the difference. In carbon, that difference is now measured in multiples, not basis points.

What to watch

Three developments will decide how fast the vintage curve becomes a visible, tradable instrument rather than a private negotiation.

Registry data standards. The major registries are under pressure to publish machine-readable serial data in a common schema. Progress there collapses the reconciliation cost that currently protects the information advantage of large intermediaries.

Compliance-program cutoffs. Each time a national or sectoral scheme sets a vintage window, it reprices the tonnes on both sides of the line. Holders of older inventory should track those cutoffs the way a bond desk tracks index-eligibility rules.

Accounting guidance. As more corporates hold carbon credits as inventory or intangible assets, the demand for a defensible mark will grow. The first widely adopted vintage-adjusted reference price will do for carbon what benchmark curves did for credit: give every participant a starting point, and make the discount for age a number rather than an argument.

Commertize's view is that carbon credits belong in a digital capital markets platform alongside gold, energy and real estate precisely because their value depends on data that can be verified at the unit level. Vintage is the clearest case. It is a fact recorded at issuance, it determines price, and it should travel with the tonne.

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