Stefan embarked on his career within the financial services industry more than 25 years ago. Starting out as a derivative structurer in 1994 at Bankers Trust, two years later he went on to establish and run Citigroup's European exotic options trading desk. There he ran one of the largest, most active, and consistently profitable equity option trading teams globally. He was credited with developing a number of innovations in the interbank option market. Latterly, Stefan ran Citi's European structured products business where he developed a range of investment products and funds. Over $50 billion of these investments were successfully placed with high net worth and institutional clients.