Where the data starts
Every company on Mycelium is anchored to an official identity before any emissions data is attached to it. We resolve companies against public registries, including Companies House and the Global Legal Entity Identifier Foundation (GLEIF), so a profile always refers to one specific legal entity rather than a name that could match several. If we cannot establish a company's identity with certainty, we do not publish a listing for it.
Reported emissions
Reported figures come from publicly available company disclosures, such as sustainability reports, annual reports and regulatory filings. We locate these documents, extract the reported greenhouse gas figures and record them against the reporting year the company states, broken down into Scope 1, Scope 2 (location and market based where given) and the fifteen GHG Protocol Scope 3 categories.
Extraction is assisted by AI and backed by automated checks, including sanity limits on emissions magnitudes and consistency checks across scopes and years. Figures that look anomalous are flagged for review rather than published as fact.
Provenance
Wherever we hold the source document, a company profile links to it, down to the pages the figures appear on. You should never have to take our word for a number. If a figure matters to you, the provenance section shows you exactly where it came from so you can check it in the original report.
Modelled estimates
Not every company reports, and few report every category. Where figures are missing we can estimate them from the company's revenue and industry classification, a process we call normalisation. Modelled values are always labelled as such and are never presented as reported data. Normalisation exists so that companies can be compared on a like for like basis, and it carries a scoring penalty that rewards companies for closing the gaps with real disclosure.
Scores
Each listing carries a Mycelium Score, which reflects the company's emissions intensity within its sector, how transparent its reporting is, whether the listing has been claimed and whether the figures were prepared by an independent third party such as a carbon accountant. Alongside it, the transparency score shows how much of a company's likely emissions footprint its reporting actually covers, weighted by the categories that matter most in its industry. The glossary explains both in detail, and our white papers cover the underlying benchmarking and scoring model.
Claims and corrections
Companies can claim their listing to confirm or correct what we hold, and claimed profiles are marked accordingly. If you spot something that looks wrong on any profile, claimed or not, please get in touch and we will review it.
Limitations to keep in mind
Corporate carbon reporting is not yet standardised. Companies draw different organisational boundaries, use different reporting periods and apply different accounting methodologies, so two similar businesses can produce figures that are not perfectly comparable. Data availability also varies by company, year and disclosure type. We surface what companies have actually published, label what we have estimated, and show our sources, but you should always read emissions comparisons with these limits in mind.
See also our data sources, the glossary and the emissions data terms of use.
