A carbon sink absorbs more
than it emits.

Forests do it. Oceans do it. No major company does it yet.

SINK — the Sustainability Index for Networked Knowledge — scores every company 0–100 using the same open formula. One rubric. Public data. Community verified. No company can pay to change their score.

We're building the world's largest open database of real sustainability scores. Every score is sourced. Every score can be challenged. Every score is transparent.

Because the planet doesn't grade on a curve.

What SINK stands for

SSustainability

What we measure. Real environmental footprint — emissions, energy, supply chain, governance.

IIndex

How we measure it. One formula, scored 0–100, applied equally to every company on Earth.

NNetworked

Community verified. Open to challenge. Every score can be disputed with evidence. Transparency by design.

KKnowledge

Data-driven. Every score backed by sources. No opinions, no vibes — just evidence.

How we operate

Same rubric for everyone

A 10-person lighting company is scored using the same 10 questions as a $400B tech giant. The formula adjusts for industry and scale — the standards don't.

Payment never influences the score

Companies can pay to be assessed. They cannot pay to change the result. Fixed-price process, public rubric, published scores. Pay for the assessment, not the outcome.

Open to challenge

Every question on every score can be challenged by anyone with evidence. Challenges are reviewed and published. We'd rather be corrected than wrong.

We grade against the planet

Scores above 75 are exceptionally rare. We don't inflate grades to make companies feel good. A score of 60+ is genuine leadership — the kind backed by verified data, science-based targets, and transparent governance.

How SINK is different

SINK
Scores funded by users, subscribers & companies seeking assessment
Public methodology — anyone can reproduce our scores
Community verification and open challenges
Free to search and share
Traditional ESG ratings
Funded by the companies being rated (conflict of interest)
Proprietary methodology — 'trust us'
Closed process, no public scrutiny
Paywalled behind enterprise contracts

Why this exists

The companies with the largest environmental footprints pay rating agencies to score them. Those agencies use secret methodologies. The results are paywalled behind enterprise contracts that cost tens of thousands of pounds per year.

The result? ExxonMobil can receive an "A" rating from one agency and a "below average" from another — for the same year of operations. Consumers, journalists, and small investors have no way to know what's real.

SINK is the alternative: one formula, public data, open methodology. The same rules for a two-person startup as for a multi-billion-dollar tech giant—because transparency shouldn't scale with power.

Help us build the database

Search for a company. Verify a score. Challenge what doesn't look right. Every contribution makes the data better.