He completed his diploma thesis Requirements in Change in Wealth Management under the lecture of Prof. Dr. Rolf Kiechl, a professor at University of Zurich, and graduated with honors designation magna cum laude.

[3] Between 1980 and 1983, Portmann completed a commercial apprenticeship at UBS in Zürich, followed by an internship at Brown Brothers Harriman & Co in New York.

In 1983, he became a junior trader at the Morgan Guaranty Trust (today part of JPMorgan Chase), a position he held until 1985.

From 1990 to 2001, he held several positions in commodities trading at Banca del Gottardo and Finter Bank in Zurich.

Since 2003, he is a director of LGT (Switzerland) AG in Zürich (after STG was taken-over by the Liechtenstein banking house).