Leaderboard: Which companies retire the highest quality carbon credits?

Companies around the world purchase and retire carbon credits as one piece of their climate action strategy (in conjunction with other measures, like reducing their operational emissions). But not all carbon credits are created equal. 

Calyx Global has conducted more than 1,000 ratings of carbon credit projects to assess how likely they are to meet their greenhouse gas emission reduction (or removal) claims—the largest such data set available. (We also rate projects for contributions to Sustainable Development Goals and environmental and social risks, though those are not included on this page—you can read about our approach to ratings here and see our overall ratings distribution here.) 

So, which companies are retiring the highest quality carbon credits? Below we list the companies with the highest average scores for transparently retired credits in 2025. We consider transparency on two metrics: (1) Do they report their carbon credit usage publicly (e.g. through a sustainability or other report); and (2) Are the vast majority of their retirements also logged publicly in the registries. We did not include companies that lacked sufficiently transparent retirement information.

The “leaders” are broken down by large buyers (over 100,000 credits retired) and overall buyers (minimum 500 credits retired). 

Top large retirees (>100,000 credits retired), 2025

The top three large buyers by average rating of credits retired, all with a BBB or higher average per Calyx Global data, are currently Salesforce, Autodesk, and Ernst & Young.

Top overall retirees (>500 credits retired minimum), 2025

The top overall companies by average rating of credits retired, all with a AA or higher average rating per Calyx Global data, are Williams College, Gatwick Airport, Vetter Pharma, and StepStone Group. 

Notes: Retirement data is based on 4 major registries: ACR, CAR, Gold, VCS. Amount is estimated, as some retirements of projects are for more than one year, in which case we pro-rated the amounts.

Calyx Global subscribers can see our larger database of Credits Retired in Major Registries on our platform. 

We hope that over time, the quality and transparency of credits retired continues to increase. We track the quality of credits issued and retired as well as credit prices here. 

Want to know your company’s rating? Reach out and we will share your letter grade.