That's not a complete picture, Prince Alwaleed owned 4.9% of Twitter as recently as the end of 2016 (the alleged espionage happened before this). It is unknown how much he owns now after his late 2017 detainment, presumably shares were either sold off, seized by Saudi authorities, or both. It's not unusual for ownership to be split among smaller entities, and there is no requirement for US companies to consolidate myriad unknown foreign stock holders into specific entities in their reports.

https://www.cnbc.com/2017/11/05/citigroup-twitter-held-by-de...