How every SYNE Rating is built.
Five products. One shared architecture. Every SYNE Rating - ESG, Sustainability, Carbon, or Supplier - is built from a weighted, published criteria framework, scored on the same AAA–D scale, and positioned on the same SYNE Index. This page explains what's common across all of them, and links to the detailed methodology behind each.
Four principles that don't change from product to product.
Whichever SYNE Rating you're reading, these four things are always true.
Published, external frameworks
Every criteria set is mapped to recognised external standards for its domain - never an internal checklist nobody outside SYNE can open.
Data quality, rated explicitly
Every framework includes a dimension scoring the quality and verifiability of the underlying data - not just the performance it describes.
Regulatory-grade independence
Operating under the EU ESG Ratings Regulation (ESMA 2023/2631) and the FCA Code of Conduct - methodology, conflicts and fees published for every product.
One shared scale & index
Every rating lands on the same AAA–D scale and the same SYNE Index, so a grade means the same thing regardless of which product produced it.
Six tiers, used identically across every product.
The composite score ranges are the same everywhere. What differs from product to product is only the criteria that feed into the score - never the scale itself.
Front Runner · Highest confidence across all dimensions, backed by rigorous, independently verified data.
Front Runner or Rising Star · Strong across most criteria, with only minor identified gaps.
Rising or Emerging Star · Material gaps identified and being actively addressed.
Emerging Star or Back Marker · Significant improvement needed across multiple dimensions.
Back Marker · Fundamental gaps in one or more core dimensions.
No material evidence of the performance being assessed.
A weighted average score is only ever a starting point. Every methodology also defines non-compensatory floors on certain critical criteria - for example, no rating can reach AAA or AA without independently verified underlying data, regardless of how strong the rest of the score is. The detailed methodology for each product specifies exactly which floors apply.
Five products. Five detailed methodology documents.
Each document below covers scope, data sources, the full criteria framework, weighting, grade assignment, governance, and appeals for that specific product.
ESG Ratings Methodology
For publicly listed and public companies. Assesses environmental performance, social performance, governance and business ethics, and controversy and disclosure quality.
Read the full methodology →Sustainability Ratings Methodology
For unlisted organisations, non-profits and institutions. Assesses environmental stewardship, social impact, governance and accountability, and transparency maturity.
Read the full methodology →Carbon Ratings Methodology
For carbon credit projects, issuers and carbon-intensity performance. Assesses additionality, permanence, MRV & data integrity, and co-benefits.
Read the full methodology →Supplier Ratings Methodology
For suppliers, vendors and distributors. Assesses financial stability, compliance & labor standards, environmental practices, and business continuity.
Read the full methodology →SYNE Index Methodology
The cross-product benchmark layer. Explains how standards alignment and data quality are calculated from each product's underlying criteria, how quadrant boundaries are set, and how the Index is refreshed as ratings update.
Read the full methodology →SYNE World Index Methodology
The country-level layer. Explains the four independent pillars scored for every tracked country, the equal-weighting and reweighting logic, the minimum coverage threshold behind an IDC classification, and the distinction between a licensed rating and an index-only position.
Read the full methodology →The same governance model runs underneath every product.
The specific criteria differ by product, but the governance process that turns criteria scores into a published rating is common to all of them.
Rating Committee
Every rating is signed off by an independent Rating Committee, separate from the lead analyst who scored it.
Analyst Independence
Analysts have no commercial relationship with the entities they rate, disclosed and monitored under SYNE's conflict-of-interest policy.
Review Cycle & Triggers
Ratings are reviewed at least annually, with interim reviews triggered by material events such as a controversy or restatement.
Appeals Process
Rated parties may request a factual accuracy review within a defined window before a rating is finalised or republished.
Every methodology is a versioned, dated document.
Methodology changes are never applied silently - each document records its own version history, and material changes are communicated to rated parties ahead of the next review cycle.
Reviewed at least annually
Every methodology document is formally reviewed at least once a year, and more often if market standards materially change.
Changes disclosed in advance
Material methodology changes are published with a disclosed effective date, ahead of being applied to a live rating.
Available on request
The full text of any methodology document, including prior versions, is available as part of SYNE's regulatory disclosure pack.
Have a question about a specific methodology?
Talk to our methodology team, or open the detailed document for the product you're rated - or being rated - under.