[2] Before joining NBIM, Tangen lived in London, where he founded and managed the hedge fund AKO Capital.
[5][6] In 2019, he was placed 6th in The Sunday Times Giving List, which ranks philanthropists from the UK based upon the proportion of personal wealth that they have given away each year.
[7] In 2020, his appointment as the chief executive officer (CEO) at NBIM[8] proved controversial[9][10] with some sources describing it as “the biggest crisis in the fund’s 24-year history.”[11] Tangen was trained in interrogation and translation in Russian in the Norwegian Intelligence Services, before he attended the Norwegian School of Economics and the Wharton School of the University of Pennsylvania as an undergraduate during 1988–92.
[15][16] The Sunday Times ranked him among the 20 most successful hedge fund managers in the UK in its 2018 Rich List.
[24] Tangen will gift his Nordic art collection to a Norwegian foundation as part of a new project planned in his hometown of Kristiansand, Norway.
[27] In May 2019, it was announced that Tangen and his wife Katja had joined The Giving Pledge, committing at least half of their wealth to philanthropic causes during their lifetime or in their will.