Chain of Custody Models and Definitions Guidance
Chain of custody models enable the transfer of materials and associated attributes through certified supply chains. They underpin the claims that can be made about an approved or certified product. A range of models exist that enable different claims, track different data points, and set various controls on the flow of materials and attributes through supply chains.
The ISEAL Chain of Custody Models and Definitions Guidance provides a shared baseline reference for different Chain of Custody (CoC) models, supporting consistency in understanding and implementation across different industries and sustainability systems. Since its initial publication in 2016, the guidance has served as a valuable resource for organisations seeking to align CoC models with credible sustainability claims.
In 2024, we launched a revision process and public consultation to ensure the guidance remains relevant and practical for today’s shifting traceability landscape. The updated 2025 version 2.0 of the guidance is now available.
The update was developed with input from an expert working group and shaped through a 75-day public consultation, which drew over 340 comments from 28 organisations.
As supply chain dynamics evolve, so must the definitions and models that we rely on. New regulations like the EU Deforestation Regulation, technological developments like blockchain, and increased corporate focus on supply chain emissions are all reshaping how we track and trust supply chain data. The 2025 guidance reflects this evolving traceability landscape and includes:
- New models like Controlled Blending and Controlled Mass Balance
- Clarified definitions and key concepts
- Lots of practical diagrams to support learning and application across sectors
The updated guidance was introduced during a launch webinar on 9 July 2025, watch here.
This guidance is aligned and complementary to the ISEAL Code of Good Practice for Sustainability Systems (‘the ISEAL Code’). It can be used as a reference to understand the different CoC models used in sustainability systems, which can help support a consistent understanding of ISEAL Code requirements relevant to CoC. It also identifies conditions under which each CoC model is appropriate for different supply chains, which can help inform discussions about which strategies may be relevant to specific clauses in the ISEAL Code. For example, truthfulness of allowed claims (8.2) and chain of custody (8.4).
For more information, contact Jessica Fryer – jessica.f@isealalliance.org.