As of December 2013, the Marine Stewardship Council (MSC) has a total of 2,543 Chain of Custody (CoC) certificates, including 155 groups, 108 multi-sites, and 2,280 single site certificates.

The MSC Certification Requirements (CR) allows Conformity Assessment Bodies (CABs) to issue three types of CoC certificates: single site, multi-site and group. According to CR version 1.3 a site as "a discrete physical location" and defines a group as "a group entity and its associated individual sites, which collectively apply for certification". However the requirement does not clearly define how to document or audit more complex organisations, particularly those with multiple sites.

Under the current system, multi-sites range from a company with two locations (sharing one CoC code) to several supermarkets with over 100 sites. Numerous certifiers have contacted the MSC for guidance on this topic. The most frequent cases are companies with a processing site and a trading site that are one legal entity. According to the CR version 1.3, these can be considered separate sites and certifiers may interpret this as each site needing a separate certificate.