On 5 April 2018 the OECD released the Second Edition of the CRS Implementation Handbook. The main change introduced by the Second Edition is the inclusion of additional guidance on identifying "Controlling Persons" of trusts.
The additional guidance provides clarity on how to identify Controlling Persons where there is a chain of ownership in a trust structure. The guidance confirms that in most cases it will be enough for a person to be a "Controlling Person" if they satisfy the "25% threshold" test outlined in the 2012 FATF.
The guidance also helpfully includes a number of flow chart type diagrams of simple trust ownership structures which illustrate when a person will be a Controlling Person.