In recent years, sustainability has become one of the key dimensions of business performance. The results obtained in terms of sustainability must be adequately communicated in suitable reports, the quality of which is determined by several factors. One of these, the breadth of information provided, plays a significant role. The aim of this paper is to measure the broadness of non-financial information in sustainability reports and correlate this to some selected variables that refer to corporate governance, i.e., the presence of an internal sustainability committee and of female directors; the characteristics of the report e.g., Sustainable Development Goals (SDG) citation; company features, number of employees, revenues, and Return On Assets ROA. For this purpose, 134 Italian companies were studied and a score based on the conformity of the NFD (non-financial disclosure) with the GRI (Global Reporting Initiative) standards was created. To test the research hypotheses, univariate analysis and multivariate regression analysis were performed. The results showed different behaviors by the companies in terms of sustainability policies. The GRISC (Global Reporting Initiative Score) has a greater concentration on mean values. Positive correlations were found between GRISC and the presence of an internal sustainability committee, SDG citation in the NFD and company size. This study offers support for policy makers and practitioners as it provides a measure of the breadth of sustainability information and relates this to the variables analyzed. The latter depend on regulatory interventions or company policies which are implemented, or could be implemented, to improve the extent of the NFD.