The AO500: A leading carbon price index
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What is the AO500 carbon price index?
The AO500 is AlliedOffsets’ leading carbon price index. The AO500 is a weighted average price across the 500 most retired carbon credit projects globally, updated three times a week. It answers the question: what does a carbon credit actually cost, based on what’s really being retired? Below is a comparison between our AO500 index and our Tradable20 Index (the price of the current 20 top most liquid and traded credits int he market).
What goes into the index?
Tailored index for strategy, procurement, risk and market analysis
Top projects
Weighted by retirement
Unique pricing inputs
AI pricing model
Data featured in
Who uses the AO500 index?
Many actors in the market are relying on the AO500 index to benchmark the latest prices and activity in the market. For example:
Corporates benchmarking purchase prices against the wider market
Journalists and analysts citing a single reference price for "carbon credits"
Brokers and developers pricing new deals
Researchers tracking market trends over time
Why the Ao500 index exists
The AO500 was launched to close a gap in the market: there was no single, reliable answer to the question everyone was asking: “what does a carbon credit actually cost?”
Rather than track the full spread of prices across the market, the AO500 focuses on the most popular projects in the market: it’s a weighted average price across the 500 most-retired projects, weighted by the volume each one has retired.
The index acts an overview and summary of the current activity in the carbon market.
Everything you want to know about the AO500
The AO500 is AlliedOffsets’ price index tracking the 500 most actively traded carbon credits in the carbon market, weighted by the volume each one has retired. It’s designed to give buyers, sellers, and analysts a single reference price for where the broader market sits, rather than relying on any one project or registry’s listing price.
The index updates three times a week using the most recent transaction data available across tracked credit types.
The AO500 is published by AlliedOffsets, built on the same underlying dataset that powers the AlliedOffsets platform: carbon offsetting projects tracked across 35+ registries spanning the globe, with coverage extending to over 39,000 carbon projects globally. Pricing inputs are drawn from tracked transactions and retirements across the market which is what allows the index to reflect where the market is actually trading rather than where any one seller is asking.
A single project’s price reflects one seller’s listing, which can be skewed by low liquidity or one-off deals. The AO500 aggregates across the market’s most-traded credits, so it reflects where transactions are actually clearing, a more reliable reference for budgeting, contracts, or benchmarking.
Yes, historical AO500 data is available dating back to 2020 on AlliedOffsets Dashboard and via our API.