He began his career in 1989 with KPMG in London, specializing in banking and large multinational Groups before joining the international food and drink group DIAGEO in 1993, to assume senior Greek and European positions in Finance and Business development. During 1998-1999 he also worked for the development of the food sector business (Pillsbury) in Middle East and North Africa. Between 2000-2002 he worked as Chief Financial Officer and Chief Restructuring Officer in an ASE listed high-tech company (part of LEVENTIS Group) and in 2003 he joined PETROLA HELLAS as Chief Financial and IT Officer.
After the legal merger and operational integration of PETROLA HELLAS with HELLENIC PETROLEUM, he was appointed as CFO of the new Group in 2005 and became a member of the Group’s Executive Committee. In 2012 he assumed the responsibility for International subsidiaries and he was Deputy CEO during the period 2014-2015 and 2017- 2019 when he became CEO.
Mr. Α. Shiamishis serves as a board member of the Hellenic Federation of Enterprises (SEV) and sits on the board of SEV Council for Sustainable Development (BCSD). He is a founding member of the American Hellenic Chamber of Commerce (AMCHAM) board of Corporate Governance and is also a member in a number of professional bodies including the Economic Chamber of Greece and ICAEW specialized faculties.