Purpose - The purpose of this paper is to establish the extent to which sustainability disclosures in a strategically important South African company have changed, in the light of the work by King. Design/methodology/approach – The paper takes the form of a content analysis of the sustainability reports of a single reporting entity, Denel (Pty) Ltd (Denel), the largest manufacturer of defence equipment in South Africa. The computer assisted textual analysis software programme CATPAC II™ was used to undertake the investigation. Findings – The paper finds that the emphasis of the sustainability reports changed each year over the period of the study. However, all the reports embody the principles and philosophical aspects of King (in 2002 and 2009). A year on year comparison of the 20 concepts identified as common to each data set over the period of the study found no substantial differences between them. This finding suggests an underlying consistency in their use by the prepares of the sustainability reports. Research limitations/implications – This research is limited to the analysis of the sustainability reports contained within Denel's 2007 to 2011 annual reports. Practical implications – The use of research techniques such as those described in this paper has practical implications for future research. Where legislative requirement requires corporate social responsibility reports to be prepared by private and public sector entities, this technique would be especially useful to establish the similarities and differences between them. Differences and the extent of the differences will be of interest to stakeholders groups, preparers and researchers as they will indicate how organisations in the different sectors view sustainability. Originality/value – Although sustainability reporting has been the subject of extensive research, longitudinal studies are limited. This longitudinal study contributes to the limited CSR literature focusing on developing countries and, in particular, African countries, as well as on the defence or armaments industry.