At the International Federation of Accountants (IFAC), Stathis heads up the development of international services for professional accountants working in business and the public and not-for-profit sectors. A key element of his work has been to publish guidance in support of professional accountants and their roles in helping to facilitate sustainable organizational success, including providing leadership on how organizations can incorporate sustainability factors into their decision making. Before moving to IFAC, he was at the Chartered Institute of Management Accountants (CIMA) responsible for planning and overseeing a program of thought leadership and research for management accountants.

Previous to his role at CIMA, Stathis was in a performance and financial management role in the UK National Health Service, particularly in relation to commissioning healthcare services and implementing better performance management and policy structures. His early experience was managing software development and localization for the computer industry.