The news was announced in a document released by the US Securities and Exchange Commission (SEC).
FILE - In this April 19, 2017 file photo, James Murdoch attends the National Geographic 2017 "Further Front" network upfront at Jazz at Lincoln Center's Frederick P. Rose Hall in NY.
James Murdoch, the younger son of the Fox and News Corp mogul, was CEO of Fox until it most of it was sold to Walt Disney Co past year.
His breaking off his ties with the family's other company is a big moment for the Murdoch family and the people who watch it closely.
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Murdoch, whose brother Lachlan runs Fox, which houses Fox News, tendered his resignation effective immediately. "We wish him the very best in his future endeavors".
New York-based News Corp also publishes major papers in Australia and the United Kingdom and owns the HarperCollins book publisher. "Kathryn and James' views on climate are well established and their frustration with some of the News Corp and Fox coverage of the topic is also well known", they said in January.
It also owns The Sun, The Times and The Sunday Times in the UK.
James and Lachlan had shared power at 21st Century Fox, but the sale of much of the Fox entertainment business to Disney in 2019 saw James depart as CEO.