The rise of the concept of sustainability reveals a pivotal shift in market thinking, thus pushing companies to reevaluate the method in conducting their decision-making processes. The main objective is to investigate the role of accounting information in decisionmaking from the point of view of Certified Accountants. Specifically, it aims to analyse the relationship between the companies' size, the usefulness of Financial Information (FI) and Management Control Information (MCI), and the company's economic performance. Supporting evidence is provided by analysis of an online questionnaire survey of professionally qualified accountants working in Portugal. We used structural equation modelling in the analysis of causal relationships between different constructs. The results show the size of the companies and their performances are directly related, so it is the larger companies that have the best economic performance. However, to improve the company's performance, it has been proven that the use of FI in decision-making is not sufficient, so the use of MCI is decisive for a good economic performance. This study highlights the importance of producing useful FI and MCI to assist decision-making and contribute to economic sustainability.