XFID: A Permanent Identifier for Extra-Financial Disclosures
XframeworkID is the open registry of extra-financial disclosure — the frameworks, opinions, reports and policies behind companies’ sustainability commitments — verified, version-tracked, and preserved with permanent identifiers (XFIDs: Extra-financial Framework Identifiers) even after the originals are moved or deleted.
What is XFID?
In the sustainable finance market, labelled bonds are backed by framework documents, reviewed by Second Party Opinion (SPO) providers, and followed by periodic impact and assurance reports. Institutional investors publish responsible investment policies, ESG integration guidelines, and climate action plans. These documents are foundational — they define the sustainability commitments that underpin instruments and investment decisions.
The problem is that these documents have no stable, universal identifiers. They are referenced by URL (which changes), by file name (which varies), or by free-text description (which is ambiguous). Over time, links break, documents move, and the connections between related disclosures are lost.
XFID solves this by assigning every document a permanent, content-based identifier — an XFID — that is computed from the text of the document itself, not from its URL or metadata. Any copy of the same document, anywhere in the world, produces the same XFID.
How XFID works
Submit
A document is submitted via the XFID API, the web interface, or ingested automatically from known issuer and SPO provider sources. PDFs are accepted; HTML pages are also supported.
Mint the XFID
Text is extracted from the document and normalized deterministically: Unicode NFC, lowercase, PDF timestamps removed, line-break hyphens collapsed, standalone page numbers stripped, URLs normalized. The canonical text is then hashed with SHA-256. The first 40 bits of the digest are Base36-encoded (mod 367) to produce a 7-character hash segment. A Luhn-mod-36 check digit is appended, yielding the final 10-character XFID.
XF - HHHHHHH - C XF — fixed prefix HHHHHHH — 7-char Base36 hash C — Luhn-mod-36 check digit Cite permanently
The XFID is immutable and content-addressable. Reference it in term sheets,
data feeds, regulatory filings, research papers, or disclosure documents.
The registry entry at xframework.id/[XFID] will always
resolve to the same document record.
Why it matters
For issuers
A stable XFID for your framework lets underwriters, investors, and data providers reference the correct document without ambiguity — even when you update your website or rebrand.
For SPO providers
Your second party opinion is linked directly to the framework XFID it assesses. The relationship is preserved in the registry even if source URLs change on either side.
For investors and analysts
Cross-reference disclosures across portfolios. Track framework versions, SPO coverage, and impact report histories using stable, machine-readable identifiers. Your own responsible investment policies and climate action plans are also permanently registered and citable.
For regulators and standards bodies
XFID provides a document-level audit trail that can be referenced in regulatory filings and referenced across jurisdictions.
Open citation policy
XFID identifiers are open to cite. There is no permission required, no license fee, and no restriction on referencing an XFID in any context — term sheets, prospectuses, data products, software, or research.
The identifier is a fact about the document, not proprietary to the registry. The registry itself provides value through its structured metadata, version history, and relationship graph — features available to subscribers.
Registry scope
The XFID registry covers extra-financial documents associated with capital market instruments and sustainable investing, including:
- Frameworks — Green bond frameworks, social bond frameworks, sustainability-linked bond frameworks
- Second Party Opinions — SPOs issued by independent reviewers against frameworks
- Assurance reports — Third-party assurance on allocation and impact reporting
- Climate Bonds Certifications — Verification reports under the Climate Bonds Standard
- Impact reports — Issuer annual reports on use-of-proceeds and impact metrics
- Investor frameworks — Responsible investment policies, ESG integration guidelines, stewardship policies, and climate action plans from institutional investors including pension funds, sovereign wealth funds, and asset managers
- Bank frameworks — Sustainable finance frameworks, lending taxonomies, transition finance frameworks, and net-zero banking commitments that define how banks classify and allocate capital for sustainability
- Prospectus sections — Relevant sustainability sections from bond prospectuses
- Final Terms — Sustainability-relevant final terms documents
Documents are indexed from public issuer, SPO provider, and institutional investor websites, and can also be submitted directly by issuers and verified organizations.
Where this is going
The registry’s coverage today is deepest in labelled bonds — the frameworks, second party opinions, impact reports and EU Green Bond reviews behind green, social and sustainability issuance. That is the beachhead, not the destination.
The ambition is the complete extra-financial record: every labelled instrument, then every disclosure a company makes about its sustainability commitments — investor policies, bank frameworks, certifications, assurance — connected, version-tracked, and permanently citable. The complement to the financial platforms: the financial data lives on your terminal; the extra-financial lives here.
In one sentence: giving the responsible-investment analyst everything the sustainability claims rest on.
Get involved
XFID is built for the sustainable finance community. Issuers, SPO providers, banks, investors, and data vendors can all contribute to and benefit from the registry.