What does GRI require regarding the use of a materiality matrix?

The use of a materiality matrix in the context of GRI reporting is a critical component for organizations to define and understand what is material to their stakeholders as well as to the organization itself. The correct assertion emphasizes that while the GRI does not mandate a specific format or the formal inclusion of a materiality matrix, it stresses that organizations must reflect significant impacts in their sustainability reporting.

This means that the emphasis is on the need to identify and prioritize sustainability topics that are significant to both the organization and its stakeholders. By doing so, organizations can ensure that they are addressing the most relevant issues in their sustainability efforts. The requirement here is about the significance of the impacts rather than the matrix's presence or dimensions.

In this context, organizations are encouraged to engage with their stakeholders to determine what matters most, rather than strictly adhering to a prescribed tool or methodology. Hence, while a materiality matrix can be useful, it is the content and significance of the issues that matter most according to GRI standards.