The billionaire Saudi prince Alwaleed bin Talal known for his investments in top tech firms such as Twitter and Apple, has been detained as part of an anti-corruption crackdown by the country's crown prince Mohammed bin Salman.
Shares in his Saudi-listed business Kingdom Holdings plunged more than nine per cent on the Saudi stock exchange Tadawul.
He was among a dozen princes to be detained along with four ministers and ten former ministers, Reuters reports.
Prince Mohammed was granted new powers by his father, King Salman, as chair of a new anti-corruption committee.
Prince Alwaleed is one of the richest men in the world with a fortune estimated at $19bn according to Bloomberg's billionaire's index.
Kingdom Holdings also boasts investments in US tech firms Lyft and Snap, as well as Citigroup, 21st Century Fox and London's Savoy Hotels, while it previously held a stake in Canary Wharf.
It swung to profit in the three months to the end of September in earnings released shortly after prince Alwaleed was detained.
The conglomerate reported a 170 per cent rise in third quarter net profit to SAR 248m (£50.6m). Revenues came in at SAR 550m, up 76 per cent on the same time last year.
Some figures for the period last year were "reclassified", though no detail was given. Saudi companies have moved to reporting in line with international accounting standards for the first time this year.