Tellef co-founded Northzone in 1996. Tellef has over the years invested companies such as LastMinute.com, Mamut Software and Trolltech.
Since 2018, Tellef is the CEO of Norfund, the Norwegian Investment Fund for Developing Countries.
Tellef was instrumental in the foundation of the Norwegian Venture Capital Association and acted as its first Chairman. He has also served as Director of both EVCA and the Swedish Venture Capital Associations.
Prior to Northzone, Tellef took part in the founding of Western Bulk Shipping, a truly global company, which he then took public as a CFO. Before this, he held the position as company secretary of another shipping and investment company – I.M. Skaugen. He has also worked as a political advisor.
Tellef holds a M.Sc. in Business Administration from the Norwegian School of Economics and a M.Sc. (Econ) from London School of Economics (1988).
Tellef is a co-founder and active board member of The Voxtra Foundation which is making targeted investments and grants in developing countries.