Marius Hermansen has resigned as chief operating officer of John Fredriksen's private company, Seatankers Management.
Although he has been in his Seatankers role for just under 18 months, Hermansen has worked for Fredriksen companies since 2014.
Hermansen told TradeWinds that the move is "fully my own decision".
"I am grateful for how much responsibility the [Fredriksen] family has given me," he said.
"I will stay for a few months to wrap up my handover."
Hermansen told TradeWinds that he will likely stay within the offshore, shipping and energy sectors, which he said are his main fields, but did not disclose what he plans to do next.
As well as resigning from his Seatankers role, Hermansen said he will also ultimately leave the boards of Fredriksen's shipping companies Flex LNG, bulker owner Golden Ocean Group and Avance Gas, of which he has been chairman since 2017.
Hermansen joined the Fredriksen group in 2014, when he joined tanker company Frontline Management as director of sale-and-purchase projects.
Prior to joining the Fredriksen group, Hermansen worked for more than 10 years at Norwegian shipbroker Fearnleys.
He was educated at the Norwegian School of Economics in Bergen, after which he began his career as a trainee in AP Moller-Maersk's finance division.
High-level shake-up
Hermansen's departure is the latest in a string of high-level personnel changes and shake-ups in the Fredriksen empire.
Fund manager Vegard Soraunet was brought in last year to restructure Fredriksen's Seatankers Group to help it invest outside shipping and oil and gas.
Seatankers said in September that Soraunet will focus on "long-term and active ownership" outside Seatankers' traditional business areas.
Aeternum Capital, led by Soraunet, formally launched at the end of January with a slate of deals and dealmakers from outside Fredriksen’s core sectors.
Fredriksen's daughter Kathrine looks poised to inherit her father's shipping interests in the longer term.
There have also been reshuffles of senior management at several different Fredriksen companies over the past couple of years.
Frontline Management chief executive Robert Hvide Macleod stepped down with immediate effect in October last year and has not yet been formally replaced.
Christian Andersen was let go from his position as chief executive of Avance Gas in April 2019 after an apparent "culture clash" with John Fredriksen, as TradeWinds reported at the time.
He was replaced by Ulrik Andersen, who a year later replaced Birgitte Ringstad Vartdal when she resigned as chief executive of Golden Ocean Management.
Kristian Sorensen joined Avance Gas from Fearnleys in January as its new chief executive.
