The Carbon Underground 200™

Identifies the top 200 dirtiest coal and oil/gas reserve owners in the world.

The Carbon Underground 200™, compiled and maintained by Fossil Free Indexes℠, identifies the top 100 coal and the top 100 oil and gas publicly-traded reserve holders globally, ranked by the potential carbon emissions content of their reported reserves.

Rankings are constructed using a reserves-based methodology with the underlying core data based on “reported” reserves. Coal reserves are the sum of proven and probable reserves based on the last reported reserves amount by mine. Reserves are allocated to listed companies based on percentage ownership of individual mines. Oil and gas companies are ranked on proven reserves (1P) net of royalty payments.

The Carbon Underground 200 relies on the IPCC Revised 1996 Guidelines for National Greenhouse Gas Inventories as a methodological framework. The calculation of CO2 emission potential requires several conversions to the raw reserves figure.

Fossil Free Indexes℠

Fossil Free Indexes provides benchmarks, research and investment solutions that support carbon-responsible investing, with an initial focus on broad market indexes ex-fossil fuels that align with the divestment movement. Embracing the transition to a low carbon economy through responsible investing, they join the growing number of analysts who believe fossil fuel companies are overvalued and a risky long-term investment based on unburnable reserves. FFI indexes and rankings are licensed for funds, ETFs, and separate accounts, as the basis for investable products and strategies. Learn more at


Mutual funds screened for Carbon Underground 200 companies by Fossil Free Funds would flag the equities of only the reserve-owning corporate entities of Carbon Underground 200 ranked companies. They would not flag non-reserve owning subsidiaries or parent companies.

If reserve-owning subsidiaries are listed separately from their parent, and their reserves are reported separately from the parent, but their emissions do not merit inclusion in the Carbon Underground 200, the equities of those subsidiaries may not be flagged by screening.

Given the continual mergers and acquisitions, closures, delisting, and IPO activities in the coal, oil, and gas industries, the Carbon Underground 200 list represents a best-efforts attempt at researching listed companies and basing the analysis on the latest available information.

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